SUSSEXITE


Mn2+BO2(OH),
manganese boron hydroxide




In the late 1860s, George J. Brush of Yale University visited the Franklin area and collected specimens of a fibrous mineral that shortly thereafter (Brush, 1868) he described as a mineral new to science: sussexite. Brush collected his specimens at the Hamburg mine, located in the northern part of the west limb of ore at Franklin, within the triangular area enclosed by Main, High, and Junction Streets. Franklin is thus the type locality for the species. The type material is a compact, white fibrous mineral in a vein in massive franklinite-rich ore, associated in the vein with pyrochroite, dolomite, and rhodochrosite. A “typical but unusually large” specimen about 17 cm long is pictured in plate 19B (opposite p. 123) of Palache’s 1935 monograph. White fibrous sussexite of a less compact, more silky form was subsequently found in the Trotter, Taylor, and Parker mines at Franklin. Most sussexite specimens from Franklin follow the general description of a white fibrous vein mineral in ore, but sussexite is not the only locally occurring mineral that can be so described. Many such Franklin and Sterling Hill specimens are sight-identified and labeled as sussexite when they are white fibrous amphiboles, fluoborite, or the mixture of fibrous amphiboles, calcite, and zincite known to collectors as “calcozincite.”  Slawson (1934), for example, noted that two purported specimens of Franklin sussexite in the University of Michigan collection proved, upon analysis, not to be that mineral. Authenticated specimens of white fibrous sussexite from Franklin and Sterling Hill remain uncommon: five examples, three from Franklin (SSX5, SSX14, and SSX25) and two from Sterling Hill (SSX17, SSX37) are in the sussexite photo gallery.

Palache (1935) mentions that in 1927, a different form of sussexite was found on the picking table at Franklin as a “dull-pink massive substance” layered with dull-yellow cherty willemite in a vein in granular franklinite-willemite ore; two excellent specimens from the 1927 find (SSX20, SSX41) are included here. While specimens from the above find are scarce, at least one subsequent find of massive pinkish-lavender sussexite was made at Franklin; unlike the earlier find, this consists of a vein in ore combining the two overall forms of sussexite: pinkish and massive, white and fibrous. In one particularly showy example (SSX27) striated massive pinkish-lavender sussexite is combined and to some extent interlayered with white fibrous sussexite in a vein on typical granular franklinite-willemite-zincite ore. Note that the striations in the massive pinkish sussexite, which is in contact with the wall rock of the vein, have the same orientation as the fibers in the white fibrous sussexite developed further into the vein. This material was re-analyzed in 1982 by Pete Dunn, who found the “dull-pink” mineral to be a mixture of sussexite and hodgkinsonite (Dunn and Bostwick, 1982).

Prior to the early 1960s, sussexite was an uncommon mineral from Franklin and virtually unknown from Sterling Hill. However, with the systematic development and exploitation of Sterling Hill’s North Orebody (NOB) between 1961 and 1978, sussexite, mostly massive and ranging in color from tan to lavender to purple, was found in abundance there (Frondel and Ito, 1965) and became the NOB’s signature mineral. Colorful and distinctive, NOB sussexite was popular with miners and collectors alike, and its variety from that part of the mine is amply demonstrated in the sussexite photo gallery. Not only does sussexite exist there in its two main forms - white to tan and fibrous, and tan to pink to purple and cherty - but also in hybrid grains of massive purplish sussexite that exhibit fibrous structure (SSX28), rarely with a distinct radiating habit (SSX4, SSX7). There are also examples of sussexite in tan bundles of parallel fibers with a massive purplish core (SSX15), and tan grains of oriented, fibrous sussexite (SSX9). Orange sussexite (SSX34), presumably colored by included zincite (Dunn, 1995, p. 642), is present but uncommon.

The North Orebody, described in detail elsewhere, was not a separate orebody but the northern extension of the Sterling Hill orebody’s east limb below 1850 level. It had been located by the early 1930s and explored via a one-compartment winze sunk from the 1850 level in the early 1940s. By 1958 the three-compartment North shaft, with its hoist on 1850 level and working levels at 100-foot intervals down to 2550 level, had been completed. During its short life the North Orebody yielded a substantial amount of ore, much of it easily distinguished on sight from ore found above 1850 level. The NOB’s south limb in particular was heavily altered by hydrothermal fluids circulating along the Zero fault, and the south limb is where many of the best specimens of sussexite, mooreite, “golden” sphalerite, and magnesiochlorophoenicite were found.

Sussexite in both its fibrous and massive forms is readily confused with other minerals. Fibrous sussexite, as noted earlier, is readily mistaken for other fibrous white or near-white minerals, including fluoborite, szaibelyite (the Mg analogue of sussexite), and fibrous amphiboles such as tremolite and anthophyllite. A positive flame test for boron (which produces a green flame) can help in distinguishing sussexite from fibrous amphiboles but not from fluoborite or szaibelyite, both of which, like sussexite, are boron minerals. Massive sussexite in its pink varieties can be confused with massive hodgkinsonite and in some specimens (SSX27) is intergrown with that mineral. Fluorescence has been of little help because our local sussexite had long been regarded as nonfluorescent.  More recently, careful scrutiny with modern LW LED flashlights revealed a dim red fluorescence in some specimens of massive pink sussexite and a dim white fluorescence in fibrous sussexite (King et al., 1922), but these properties are not diagnostic. In general, semiquantitative or quantitative chemical tests (to establish Mg:Mn ratio) or X-ray methods are recommended for positive identification.  Incidentally, X-ray diffraction peaks of minerals in the sussexite-szaibelyite series have been shown to shift systematically with composition, enabling the composition of unanalyzed specimens to be estimated from the X-ray data (e.g., Takéuchi, 1957).

Franklin is the type locality for sussexite, but Sterling Hill has yielded by far the most specimens. Worldwide, sussexite remains a rare mineral that has been found in small amounts, in its fibrous habit and from white to brown in color, at about two dozen other localities in the United States, Europe, Japan, Africa, Australia, and North Korea.

References

Brush, G.J. (1868a), New borate from Mine Hill, Franklin, Sussex Co., New Jersey - sussexite. American Journal of Science, 2nd Series, vol. 46, p. 140. [Announcement of the discovery of sussexite at Franklin; description followed in Brush 1868b]

Brush, G.J. (1868b), On sussexite, a new borate from Mine Hill, Franklin Furnace, Sussex County, New Jersey. American Journal of Science, 2nd series, vol. 46, p. 240-243. [First description and analysis of the species]

Dunn, P.J. (1995), Franklin and Sterling Hill, New Jersey:  the world’s most magnificent mineral deposits:  Privately published in five volumes, 755 pp. [Description of sussexite on p. 642-643]

Dunn, P.J. and Bostwick, R.C. (1982), Hodgkinsonite from Franklin and Sterling Hill, New Jersey: a review. Mineralogical Record, vol. 13, p. 229-232. [Establishes that some specimens of massive sussexite from Franklin are a mixture of that mineral with hodgkinsonite]

Edwards, F.Z. (1966), The minerals of Sterling Hill 1962-65. The Picking Table, vol. 7, no. 2, p. 3-15. [On p. 13, a one-paragraph description of sussexite found in abundance in the North Orebody upon reopening of the Sterling mine in January 1962]

Edwards, F.Z. (1968), The exclusive minerals of Franklin/Ogdensburg, N.J. (as of January 1968). The Picking Table, vol. 9. no. 1, p. 11-17. [Removes sussexite from the list of minerals found only in the Franklin-Ogdensburg area]

Frondel, C. (1972), The minerals of Franklin and Sterling Hill - a checklist. Wiley Interscience, New York, 94 pp. [One-paragraph description of sussexite on p. 79]

Frondel, C. and Ito, J. (1965), Sussexite from Sterling Hill, New Jersey. American Mineralogist, vol. 50, nos. 3 and 4, p. 502-503. [First published account of sussexite from Sterling Hill, as opposed to Franklin. Describes grains of sussexite in altered ore as composed of parallel aggregates of fibers and provides a chemical analysis]

Gruner, J.W. (1932), Magnesiosussexite, a new mineral from a Michigan iron mine, isomorphous with sussexite and camsellite.  American Mineralogist, vol. 17, no. 11, p. 509-513. [Provides X-ray powder diffraction data for Franklin sussexite]

King, V.T., King, N.E., Betancourt, P.P., Bostwick, R.C., Chin, Peter, Hecht, T.J., Kuitems, S.M., Moritz, Harold, Nemetz, J.D., Nikischer, A.J., Sanford, Stephen, Van Fleet, J.A., and Verbeek, E.R. (2022), The Mineralogy of Franklin and Ogdensburg, New Jersey-A Photographic Celebration. Privately published, 1400 pp. [Fluorescence of sussexite briefly described on p. 27-28; photos of fluorescing specimens on p. 192-193; photos under white light on p. 1103-1105]

Moore, P.B. and Araki, T. (1974), Roweite, Ca2Mn2+2(OH)4[B4O7(OH)2]: its atomic arrangement. American Mineralogist, vol. 59, nos. 1 and 2, p. 60-65. [Briefly discusses aspects of the crystal structure of sussexite in relation to the pH (basic) and temperature (low to moderate hydrothermal) of its crystallization environment]

Palache, C. (1928), Mineralogical notes on Franklin and Sterling Hill, New Jersey. American Mineralogist, vol. 13, no. 7, p. 297-329. [Brief description, optical data, and a chemical analysis of a new habit of sussexite on p. 323]

Palache, Charles (1935), The minerals of Franklin and Sterling Hill, Sussex County, New Jersey:  U.S. Geological Survey Professional Paper 180, 135 pp. [Description, optical data, and chemical analyses of sussexite on p. 126-127]

Penfield, S.L. and Sperry, E.S. (1888), Mineralogical Notes; 4. Sussexite from Mine Hill, Franklin, N.J. American Journal of Science, 3rd series, vol. 36, p. 323.

Poitevin, E. and Ellsworth, H.V. (1924), New optical data for analyzed sussexite. American Mineralogist, vol. 9, no. 9, p. 188-190. [Attributes anomalous optical data previously published for sussexite to confusion of that mineral with chrysotile. Provides new optical and chemical data for a proven sussexite specimen from Franklin]

Schaller, W. (1942), The identity of ascharite, camsellite, and ß-ascharite with szaibelyite; and some relations of the magnesium borate minerals. American Mineralogist, vol. 27, no. 7, p. 467-486. [Discusses variation in indices of refraction and specific gravity with composition in the sussexite-szaibelyite series, using, in part, sussexite specimens from Franklin]

Slawson, C.B. (1934), Sussexite from Iron County, Michigan. American Mineralogist, vol. 19, no. 12, p. 575-577. [Announces a new locality for sussexite and notes that the X-ray diffraction pattern of the mineral shows it is better crystallized than the Franklin material.  Also notes that neither of two purported sussexite specimens from Franklin in the University of Michigan museum are that mineral]

Takéuchi, Y. (1957), The interpretation of X-ray powder diffraction patterns of the szaibelyite-sussexite series. Mineralogical Journal (Japan), vol. 2, issue 2, p. 78-89. [Provides indexed powder diffraction data and lattice constants for sussexite and szaibelyite.  Suggests that the chemical composition of intermediate members of the sussexite-szaibelyite compositional series can be determined from shifts in the positions of X-ray diffraction peaks]



Images

Massive Habit name used for masses of crystals that have no distinctive geometry. 

Fibrous Habit name used when minerals occur in very fine fiber-like crystals. They are often so fine that they look like fine hair.

Fibrous, radiating Minerals occurring in slender fiber-like crystals fanning out from a central point.

Fibrous, in fascicles Minerals occurring in a bundle of very fine fiber-like crystals.

Platy Thin sheets

Gemstone Shiny jewelry quality


Massive





Purplish sussexite with orange zincite, bordered by calcite, Sterling mine, Ogdensburg
Earl R. Verbeek
A 13-cm pod of purplish sussexite with orange zincite, bordered by calcite in altered granular ore. This compact, colorful variety of sussexite is formed of laths of massed fibers and is informally known as “gem grade” sussexite as pieces of it have been cut and polished to make attractive cabochons (e.g., SSX36). It was found at Sterling Hill in the south limb of the North Orebody. The most abundant find included this specimen and was made above 2350 level in 11 pillar during the final stages of mining in late 1977 and early 1978. The ore in this remaining part of the pillar, which was cut off on its east side by the Zero fault, was too fractured to mine safely, so holes were drilled from the level as far up as practical, and a large blast set off. When the muck pile was wet down following the blast, this colorful material was noticed, and drill runner Chuck James and the NOB crew recovered what they could. This example is from the collection of Richard C. Bostwick.

Identifier: SSX1a
Locality: 11 pillar above 2350 level, South limb of the North Orebody near the Zero fault, Sterling mine, Ogdensburg
Specimen size: 17 x 12 x 8 cm





Cherty salmon-colored sussexite in lean franklinite-willemite-calcite ore, Sterling mine, Ogdensburg
Earl R. Verbeek
Cherty salmon-colored sussexite, an unusual color for the mineral, in lean franklinite-willemite-calcite ore. This specimen is from the collection of Richard C. Bostwick.

Identifier: SSX2a
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 9 x 8 x 4 cm





Purplish sussexite, brownish orange zincite, white calcite, Sterling mine, Ogdensburg
Earl R. Verbeek
A large piece of massive, purplish sussexite that was a standout in the SPEX/Gerstmann collection and is now on display at the Franklin Mineral Museum, where it is cataloged as FMM-1441. Like similar massive sussexites (e.g. SSX1 and SSX33) it is from the South limb of the North Orebody and was probably found close to the Zero fault. This  specimen, sawn and polished on the back, is visually distinctive for the contrast between brownish orange zincite, purplish sussexite, and white calcite. Note that zincite of this sort from the North Orebody has been hydrothermally etched and is fairly fragile; it is locally called “rotten zincite.” Like the recrystallized yellow zincite from the upper levels of the West limb of the main Sterling Hill orebody, “rotten zincite” from the NOB’s South limb usually fluoresces yellow under longwave UV.

Identifier: SSX16a
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 26 x 12 x 4 cm



Purplish sussexite, brownish orange zincite, white calcite, Sterling mine, Ogdensburg
Earl R. Verbeek
The reverse side of specimen FMM-1441, showing the rich color and intricate texture of the intergrown grains of sussexite. Note, toward the right, the small, zincite-lined voids in the altered, solution-etched ore, which contains franklinite as the only surviving original phase.

Identifier: SSX16b
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 26 x 12 x 4 cm





Lavender cherty sussexite, calcite, altered willemite-franklinite-calcite ore, Sterling mine, Ogdensburg
Earl R. Verbeek
A showy example of lavender cherty sussexite from Sterling Hill’s North Orebody, bordered by calcite, in altered willemite-franklinite-calcite ore. Under shortwave ultraviolet radiation (SW UV) most of the brownish-red willemite in the ore fluoresces green, but within about 3 cm of the sussexite-calcite mass the willemite is altered and nonfluorescent, though there is little or no visible difference in daylight between the altered and unaltered willemite. As mentioned in specimen SSX29, the steeply inclined fractures in the sussexite are joints. This specimen is from the SPEX/Gerstmann collection and is on display at the Franklin Mineral Museum, where it is cataloged as FMM-1439.

Identifier: SSX19a
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 11 x 10 x 2.5 cm





Sussexite, orange secondary zincite, calcite, Sterling mine, Ogdensburg
Pete J. Dunn
An instructive cross section through the interior of a “rare mineral pod” from the North Orebody, showing pink, concentrically layered sussexite enclosing an irregular mass of fine-grained, orange, secondary zincite. Surrounding the sussexite is coarse-grained calcite cut by irregular zincite veinlets. The dull black mineral at lower left, with orange zincite, is probably franklinite in highly altered ore. The cavity-filling nature of some Sterling Mine sussexite is especially evident in this specimen, which has been sawn to best show the textural relations of the minerals to advantage. A black-and-white version of this photograph was published as Figure 12-39 on p. 309 of Pete J. Dunn’s 1995 treatise on the local minerals. The specimen is no. 164055 of the Smithsonian Institution, where for many years Dr. Dunn worked as a mineralogist.

Identifier: SSX39a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 14 cm in maximum dimension





Pale pink sussexite, hematite-strained ore, calcite, Sterling mine, Ogdensburg
Richard Schnurr
Unusually pale pink, massive sussexite cementing fragments of altered, hematite-strained ore. Another prize from the SPEX/Gerstmann collection, this specimen is on display in the Franklin Mineral Museum under catalog no. FMM-381. See also the close-up view of photo SSX42b.

Identifier: SSX42a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 9 x 8 x 4 cm



Pale pink sussexite, hematite-strained ore, calcite, Sterling mine, Ogdensburg
Richard Schnurr
A close-up view of a hematite-stained ore fragment embedded in sussexite from the same specimen shown in photo SSX42a. Note the concentric layering: the ore is rimmed first by white calcite, then dark brown serpentine(?), and finally by a thin, reddish-brown zone of hematite-stained sussexite. The hematite probably formed from iron leached into solution by incipient hydrothermal alteration of franklinite in the ore. Willemite in similarly altered ore is often serpentinized and rendered minimally to nonfluorescent in the process. Field of view is about 3.6 cm across.

Identifier: SSX42b
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 9 x 8 x 4 cm





Pale lavender sussexite, calcite, serpentinized, franklinite-willemite-calcite ore, Sterling mine, Ogdensburg
Richard Schnurr
A large mass or layer of pale to very pale lavender sussexite, bordered by calcite on both sides, in altered, serpentinized, franklinite-willemite-calcite ore from the North Orebody at Sterling Hill. This specimen once belonged to Robert Shaw, who, as a teenager in the 1960s, used to hitch rides to Franklin to purchase specimens. Decades later it was purchased by Earl R. Verbeek, who entered it into his collection as specimen ERV-1601 and in 2021 donated it to the Franklin Mineral Museum, where it remains on display. Its catalog number is FMM-7368.

Identifier: SSX21a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 13 x 12 x 12 cm





Bird’s-eye sussexite with pyrochroite and zincite, calcite, Sterling mine, Ogdensburg
Earl R. Verbeek
“Bird’s-eye” sussexite with pyrochroite and zincite, from the South limb of the North Orebody at Sterling Hill. This is visually notable for contorted parallel layers of lavender sussexite, and black pyrochroite with white-to-cream calcite, with films and veinlets of orange-red zincite. Calcite-veined, franklinite-rich ore is visible in the lower right corner. This unusually esthetic specimen is from the Steinmetz collection, bought and dispersed by the Sterling Hill Mining Museum in the late 1990s. “Steiny” was a Sterling Hill miner who after retiring owned a liquor store on Route 517 in the middle of Ogdensburg. His collection was on display in a room behind the store’s salesroom and was famous for the best tennantite crystals found at Sterling Hill. He was proud of his minerals, and of putting his son through MIT. “Steiny” had worked at Sterling Hill for Al Smith and other legendary bosses, had a keen eye, and collected his suite of North Orebody material early during its mining. This specimen is now in the collection of Richard C. Bostwick.

Identifier: SSX22a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 10 x 8.5 x 3 cm





Richly colored sussexite mass in lean calcite-franklinite-willemite ore, Sterling mine, Ogdensburg
Earl R. Verbeek
A large, richly colored sussexite mass in lean calcite-franklinite-willemite ore from Sterling Hill’s North Orebody. As its label indicates, this specimen was displayed in the Franklin and Sterling Hill “daylight” case that was part of the American Mineral Treasures Exhibition at the 2008 Tucson and Mineral Show. (The contents of the case were from many collections but were assembled through the efforts of the Franklin Mineral Museum and Sterling Hill Mining Museum.) Notable aspects include this piece’s size, the coloring of the sussexite along what appear to be healed joints (pinkish red along the joints and pinkish lavender elsewhere), and the presence in the sussexite of rounded pieces of lean ore that are rimmed with calcite and are in the process of hydrothermal alteration and replacement by sussexite. The ore matrix is visible along the left and right edges of the specimen, where the partial breakdown of original franklinite to form hematite has locally stained the ore red. The specimen is no. ERV-1911 in the collection of Earl R. Verbeek.

Identifier: SSX26a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 15 x 14 x 9 cm





Pinkish-lavender, cherty sussexite, calcite, franklinite, Sterling mine, Ogdensburg
Earl R. Verbeek
An attractive mass of pinkish-lavender, cherty sussexite rimmed by buff-colored calcite in a matrix of hydrothermally altered ore. The calcite in the ore has been colored reddish-brown by the partial hydrothermal breakdown of franklinite to form microscopic, disseminated grains of hematite. The parallel fractures in the sussexite are joints, geologically akin to the common but much larger joints often seen in rock exposures. Joints can form in minerals as well as rocks and are most likely to form in minerals that are mechanically homogeneous, either because they lack cleavage (e.g., franklinite, garnet) or because they have formed as compact, very fine-grained aggregates, as here. This specimen is no. ERV-116 in the collection of Earl R. Verbeek.

Identifier: SSX29a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 14 x 11 x 5 cm





Pinkish-lavender cherty sussexite, calcite. zincite, franklinite-willemite ore, pyrochroite, Sterling mine, Ogdensburg
Earl R. Verbeek
Massive, pinkish-lavender cherty sussexite, bordered by buff-colored calcite in a matrix of hydrothermally altered franklinite-willemite ore, and visually set off by bright orange zincite, here a late-stage alteration mineral. Note the zincite haloes around the black pyrochroite mass left of center, and bordering altered ore on the right. This is specimen ERV-1909 in the collection of Earl R. Verbeek.

Identifier: SSX30a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 13 x 10 x 5 cm





Deep pink to brownish-pink sussexite, franklinite, calcite, willemite, serpentine, Sterling mine, Ogdensburg
Pete J. Dunn
A gorgeous specimen from the Smithsonian Institution, featuring a large mass of very fine-grained (“cherty”), deep pink to brownish-pink sussexite bordered by nearly white calcite. The bottom third of the specimen is mostly altered ore consisting of franklinite (black), calcite (white), and willemite (brown). The willemite has probably been replaced largely by serpentine. A black-and-white version of this photograph appeared as Figure 24-17 on p. 643 in Dunn (1995). The specimen is no. R15679 of the Smithsonian Institution.

Identifier: SSX33a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 21 cm in maximum dimension





Brick-red to orange sussexite, calcite, pyrochroite, Sterling mine, Ogdensburg
Earl R. Verbeek
Brick-red to orange, massive sussexite (unusual color) associated with white calcite, minor black pyrochroite, and a little brown, translucent serpentine. From the Paul Chorney collection, this specimen is on exhibit in the Sterling Hill Mining Museum.

Identifier: SSX34a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 17 x 9 x 8 cm





Vein of dull pinkish-lavender sussexite, franklinite-willemite ore, Sterling mine, Ogdensburg
Earl R. Verbeek
An irregular vein of dull pinkish-lavender sussexite, ranging from 2 cm to 3 cm in width and tinted brownish orange along its margins, in altered franklinite-willemite ore that has been serpentinized by solutions from the Zero fault and pulverized by movement along that fault. This specimen is from the Ray Latawiec collection of Franklin and Sterling Hill “bands,” purchased in 2013 by the Sterling Hill Mining Museum; it has been cataloged as specimen SHMM-1827, and is on display there.

Identifier: SSX31a
Locality: 11 pillar below 2350 level, South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 9 x 7 x 3.5 cm





Lavender-colored sussexite, yellow willemite, franklinite-willemite-zincite ore, Franklin mine, Franklin
Richard Schnurr
A fine and rare example of the lavender-colored massive sussexite discovered at Franklin in 1927 and described by Charles Palache (1928) before similar-appearing “cherty” sussexite was found at Sterling Hill. In overall appearance this Franklin find has little in common with Sterling Hill cherty sussexite specimens except for the sussexite itself. Here sussexite is the pinkish-lavender mineral seen as layers in a vein of cherty yellow willemite, with stringers of orange zincite, on massive granular franklinite-willemite-zincite ore typical of Franklin. This example was no. 21158 in the collection of the Academy of Natural Sciences of Philadelphia and was obtained by the Franklin Mineral Museum in November 2007, where it is now on display as no. FMM-7049.

Identifier: SSX20c
Locality: Franklin mine, Franklin
Specimen size: 11.5 x 7 x 5.5 cm





Pinkish-lavender sussexite, granular franklinite-willemite ore, Franklin mine, Franklin
Earl R. Verbeek
Pinkish-lavender sussexite interlayered with white to tannish-yellow willemite, part of a thick vein cutting granular franklinite-willemite ore. Specimens such as this, from Franklin rather than Sterling Hill, are seen occasionally in some institutional collections but are rare on the market today. This one belongs to the Sterling Hill Mining Museum and is their specimen SHMM-2288. Previously it was in the collection of Tom Fitzpatrick (his no. 316) and later belonged to Sterling Hill miner John Kolic, who obtained it in March 1981 from legendary Franklin dealer, Ewald Gerstmann, and added it to his collection as specimen no. 401. This specimen is from the same find as SSX20.

Identifier: SSX41a
Locality: Franklin mine, Franklin
Specimen size: 7.5 x 7.5 x 4 cm





Pink sussexite, yellow willemite, calcite, granular franklinite-willemite ore, Franklin mine, Franklin
Pete J. Dunn
This specimen, a polished cut through a thinly layered vein about 4 cm thick, features pink sussexite, yellow willemite, and nearly white calcite in a matrix of altered, granular, franklinite-willemite ore. This specimen was shown in a black-and-white photo as Figure 12-44 in Dunn (1995, p. 311) and is here shown in color. Dunn called attention to the nonsymmetrical arrangement of mineral layers in the vein, indicating that the depositional sequence was more complex than simple layer accretion onto the two walls of an open fracture but instead involved multiple events. Note also the “bleached” zone in the ore immediately adjacent to the vein, a legacy of hydrothermal fluid flow. This is specimen R6606 in the mineral collection of the Smithsonian Institution and is probably from the same find as specimens SSX20 and SSX41.

Identifier: SSX40a
Locality: Franklin mine, Franklin
Specimen size: 12 cm in maximum dimension



Fibrous





Coarse fibrous cream-white sussexite, vein, high-grade franklinite-zincite-tephroite ore, Franklin mine, Franklin
Earl R. Verbeek
Coarse fibrous cream-white sussexite 3-5 mm thick from Franklin, part of a vein filling on high-grade franklinite-zincite-tephroite ore, which in turn is in contact with a layer of high-grade franklinite-willemite-zincite ore. This specimen matches Palache’s description of type sussexite, and is a fine example from the collection of Steven Phillips; previously it was in Ed Roedder’s collection.

Identifier: SSX5a
Locality: Franklin mine, Franklin
Specimen size: 6 x 5 x 4 cm





White to cream-colored fibrous sussexite, franklinite and pale green willemite, Franklin mine, Franklin
Earl R. Verbeek
White to cream-colored fibrous sussexite from Franklin, coating a fracture surface in high-grade gneissic ore composed of franklinite and pale green willemite. The fibrous sussexite is locally intergrown with pinkish cherty sussexite. Specimens like this from Franklin are rare; this was no. 234 in the Richard Hauck collection and is now in the collection of Stephen Phillips. It may be from the same find as SSX27.

Identifier: SSX14a
Locality: Franklin mine, Franklin
Specimen size: 12 x 10 x 4 cm





Fibrous white sussexite, calcite, willemite, Sterling Hill, Ogdensburg
Earl R. Verbeek
Coarsely fibrous white sussexite coating a fracture surface on a slab of lean ore (calcite with scattered willemite) from Sterling Hill. The back of the specimen is also coated with sussexite, and willemite veinlets cut the calcite parallel to the sussexite-bearing faces. Its location in the Sterling mine is not known, but like SSX16 this is a large and impressive display specimen of sussexite from the SPEX/Gerstmann collection. It is on exhibit at the Franklin Mineral Museum and is cataloged as FMM-1442. 

Identifier: SSX17c
Locality: Sterling mine, Sterling Hill, Ogdensburg
Specimen size: 16 x 11 x 5.5 cm



Fibrous white sussexite, calcite, willemite, Sterling Hill, Ogdensburg
Earl R. Verbeek
Close-up view of the coarse sussexite fibers on specimen SSX17. Horizontal field of view is about 7.5 cm.

Identifier: SSX17d
Locality: Sterling mine, Sterling Hill, Ogdensburg
Specimen size: 16 x 11 x 5.5 cm





Fibrous white-to-pinkish sussexite, oxidized pyrochroite, Franklin mine, Franklin
Earl R. Verbeek
Fibrous, white-to-pinkish sussexite coating black, oxidized pyrochroite in an esthetically appealing and unusual, perhaps unique, specimen from Franklin. The sussexite locally becomes lavender in color and cherty in texture toward its contacts with the pyrochroite, as seen in the photograph. This extraordinary piece, once no. 754 in the collection of Richard Hauck, is now in Earl Verbeek’s collection as specimen ERV-1910.

Identifier: SSX25a
Locality: Franklin mine, Franklin
Specimen size: 15 x 10 x 5.5 cm





White to pale brown fibrous sussexite, pyrochroite, Sterling mine, Ogdensburg
Earl R. Verbeek
A mass of fine-grained black pyrochroite interlayered with white to pale brown, fibrous sussexite from a fault zone at Sterling Hill. Sussexite in this form much resembles chrysotile asbestos; note the flexible fibers. This is specimen SHMM-1258 of the Sterling Hill Mining Museum.

Identifier: SSX37a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 10 x 6 x 5 cm





Pinkish-lavender sussexite, fibrous sussexite, willemite and franklinite, Franklin mine, Franklin
Earl R. Verbeek
A slickenside in granular Franklin franklinite-willemite-zincite ore, coated with massive pinkish-lavender sussexite with a splintery, almost fibrous texture, grading into white fibrous sussexite. This is apparently the first find of sussexite from the Franklin and Sterling Hill area to combine white fibrous sussexite with pinkish massive sussexite. The massive sussexite, as shown by Dunn and Bostwick (1982), is intergrown with hodgkinsonite. This remarkable specimen was in John E. MacDonald’s collection, catalog no. JEM 1028, and bears an earlier marking, no. 44C, in black ink on white paint, but that collector is unknown. It is now no. ERV-442 in the collection of Earl Verbeek. Photo SSX27b shows a side view of this same piece.

Identifier: SSX27a
Locality: Franklin mine, Franklin
Specimen size: 9 x 6.5 x 4.5 cm



Pinkish-lavender sussexite, fibrous sussexite, willemite and franklinite, Franklin mine, Franklin
Earl R. Verbeek
Side view of specimen shown in photo SSX27a. Note the flattened grains of willemite and franklinite in the ore, which collectively define a gneissic foliation dipping to the right. The fault upon which the sussexite was deposited cuts this foliation at a high angle. Note here that each splinter and fiber of sussexite is attached to the ore on its right end and grew toward the left, within a progressively dilating void, as faulting gradually took place. Such material is “gold” to geologists because the fibers provide a detailed record of the movement of one fault block relative to the other.

Identifier: SSX27b
Locality: Franklin mine, Franklin
Specimen size: 9 x 6.5 x 4.5 cm



Fibrous, radiating





Radiating laths of purplish sussexite, North Orebody, Sterling mine, Ogdensburg
Earl R. Verbeek
Radiating laths of purplish sussexite, with a splintery to fibrous texture, from the South limb of the North Orebody at Sterling Hill. This find was made in 1977 by drill runner John Anderson and comes from below the 2250 level in 3 pillar. Similar material, with partial and complete rosettes of sussexite, was known previously from the NOB but is rare; see SSX7 for an example. So far none of the earlier specimens have come with a location or date, but probably were collected earlier in an adjacent stope. The 1977 find yielded on the order of 20 to 30 specimens and is the most prolific. This specimen of “radiating sussexite,” with a complete rosette about 5 cm in diameter, was collected in situ by Richard C. Bostwick and is in his collection.

Identifier: SSX4a
Locality: 3 pillar below 2250 level, South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 9 x 6.5 x 4 cm





Rosette of “radiating sussexite”, oxidized pyrochroite, calcium, Sterling Hill, Ogdensburg
Earl R. Verbeek
A complete 2 x 3 cm rosette of “radiating sussexite” with small, irregular masses of black, oxidized pyrochroite, in hydrothermally altered lean ore (chiefly calcite and dolomite with a few grains of franklinite) from the South limb of the North Orebody. Specimens of this quality are rare, and this example from Steven Phillips’ collection, which was specimen JEM 1482 in the collection of John MacDonald, probably predates the 1977 find shown in SSX4.

Identifier: SSX7a
Locality: South limb of the North Orebody, Sterling mine, Sterling Hill, Ogdensburg
Specimen size: 9 x 6 x 5 cm



Fibrous, in fascicles





Tan to brown, fibrous to splintery sussexite, pyrochroite, zincite, calcite, Sterling Hill, Ogdensburg
Richard Schnurr
Tan to brown, fibrous to splintery sussexite with dull black masses of pyrochroite and a little orange zincite. Note the layered aspect of this marvelous example. Starting at lower right is altered, granular zinc ore, succeeded upward by white calcite and thin layers of massive, “cherty,” pink to lavender and brown sussexite. Next is a lenticular mass of brown, fine-grained sussexite, the top of which in places (center of specimen) grades into somewhat coarser-grained, lavender sussexite. This is overlain by a thick layer of tan to brown sussexite in lathlike grains arranged at high angles to the layer boundaries. Each of these laths is composed of splintery to fibrous sussexite. Toward the top of this layer appear small, scattered grains of orange zincite. Atop all of this is massive, fine-grained black pyrochroite. This specimen, FMM-7801 of the Franklin Mineral Museum, is on display in Baum Hall and was purchased from collector-dealer Mark Leger. Compare to specimens SSX10 and SSX15.

Identifier: SSX44a
Locality: South limb of the North Orebody, Sterling mine, Sterling Hill, Ogdensburg
Specimen size: 12 x 6 x 5 cm





Pinkish-lavender cherty sussexite, tan fibrous sussexite, zincite, Sterling mine, Ogdensburg
Earl R. Verbeek
A remarkable specimen from Sterling Hill’s North Orebody that displays obvious segregations of, and transitions between, both major forms of sussexite: pinkish-lavender cherty sussexite, and laths of tan fibrous sussexite which in this example appear to be pseudomorphs after blocky crystals of an earlier mineral. Note that the sussexite fibers are mostly parallel to the precursor mineral, but at right angles to it in places along the crystal margins. The orange traces are zincite, and the black areas are probably pyrochroite. This is another showpiece from the collection of Steven Phillips.

Identifier: SSX9a
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 13.5 x 8 x 8 cm





Cherty pinkish-lavender sussexite, calcite, tan fibrous sussexite, zincite, pyrochroite, Sterling mine, Ogdensburg
Earl R. Verbeek
Part of a North Orebody rare mineral pod, showing a clear sequence of hydrothermal alteration from lean ore to the center of the pod, and highlighting the two major forms of sussexite. The ore, to the bottom and right of the photo, is mostly serpentinized and dolomitized calcite with rounded grains of black franklinite and traces of willemite best seen under shortwave UV. The rare mineral pod has a thin, discontinuous rim of brownish serpentine, then calcite, then a layer of cherty pinkish-lavender sussexite passing upward to laths of tan fibrous sussexite. Touches of orange zincite and black oxidized pyrochroite complete the picture. This NOB masterpiece, once no. 818 in the Richard Hauck collection, is now in the collection of Steven Phillips. Compare to specimens SSX44 and SSX15; the sequence is similar.

Identifier: SSX10a
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 9 x 7 x 5 cm





Cherty and fibrous sussexite, franklinite, Sterling mine, Ogdensburg
Earl R. Verbeek
A sussexite-dominated rare mineral pod from the South Limb of the North Orebody at Sterling Hill. Like specimens SSX10 and SSX44, this shows the cherty and fibrous forms of sussexite, with cherty sussexite (here a dull purplish brown) along the rim of the pod (right side), and tan fibrous sussexite developed toward the center of the pod. In places on this specimen are laths of fibrous sussexite with cores of pinkish-purple cherty sussexite; these have been called sussexite “crystals,” but this is a misnomer. As with specimen SSX10, the matrix of SSX15 is hydrothermally altered ore, with franklinite the only ore mineral left visible. Specimen SSX15 is from the collection of Richard C. Bostwick.

Identifier: SSX15a
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 13 x 8 x 6 cm



Cherty and fibrous sussexite, franklinite, Sterling mine, Ogdensburg
Earl R. Verbeek
This is the “back” side of the same specimen shown in photo SSX15a, but here the transition from altered ore (base of specimen) to massive brown sussexite and then to tan fibrous sussexite is more readily apparent. Note also the thin layers of pinkish cherty sussexite between the thicker brown sussexite and ore, and the similarity of this sequence to that of specimen SSX44.

Identifier: SSX15b
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 13 x 8 x 6 cm





Pinkish-lavender-to-purple sussexite, franklinite-willemite-calcite ore, serpentine, hematite, Sterling mine, Ogdensburg
Earl R. Verbeek
A sizeable mass of pinkish-lavender-to-purple sussexite, composed of elongated, tightly intergrown grains with a splintery to fibrous structure, similar in appearance to the “gem-grade” sussexite of SSX1. It’s a classic example of the type of sussexite referred to by Frondel (1972, p. 79) as “coarse granular aggregates in which each grain is itself a subparallel aggregate of minute crystals.” Frondel and Ito (1965) had previously shown, through X-ray study, that the “minute crystals” are fibers arranged in parallel, which accounts for the silky luster and splintery fracture of this material. The matrix, visible on upper right and lower left, is hydrothermally altered franklinite-willemite-calcite ore with brown serpentine and reddish-brown hematite. This fine example was in the collection of John E. MacDonald as JEM 1484 and is now specimen ERV-403 in the collection of Earl R. Verbeek.

Identifier: SSX28a
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 14.5 x 14 x 7 cm



Pinkish-lavender-to-purple sussexite, franklinite-willemite-calcite ore, serpentine, hematite, Sterling mine, Ogdensburg
Earl R. Verbeek
A close-up view of a portion of the specimen portrayed above, showing the fibrous nature of the individual sussexite grains. The fibers in general are parallel to the long dimension of each grain and in some grains are gently curved.

Identifier: SSX28b
Locality: South limb of the North orebody, Sterling mine, Ogdensburg
Specimen size: 14.5 x 14 x 7 cm



Platy





Sussexite in reddish-pink to pale pink lamellae, Sterling mine, Ogdensburg
Earl R. Verbeek
Sussexite in reddish-pink to pale pink lamellae, from the South limb of the North Orebody at Sterling Hill. The lamellar sussexite in this example is apparently part of a pod or lens of sussexite bordered with layers of calcite and cherty pinkish sussexite. Also called platy or layered sussexite, this textural variety is another variation on the general theme of cherty, pink-to-purple-tinted sussexite. The matrix of this specimen, visible on the bottom and upper right corner, is calcite with minor franklinite and brown serpentine. This piece is from the collection of Richard C. Bostwick.

Identifier: SSX3a
Locality: South limb of the North Orebody, Sterling mine, Ogdensburg
Specimen size: 7.5. x 6 x 3 cm



Gemstone





Deep pink sussexite cabochon, wth franklinite-calcite ore, Sterling mine, Ogdensburg
Liz Schneider
A mounted cabochon of deep pink sussexite from the Sterling mine. Note the small, included fragments of franklinite-calcite ore. Formerly in the John Kolic collection, this cabochon is now specimen SHMM-2315 of the Sterling Hill Mining Museum.

Identifier: SSX36b
Locality: Sterling mine, Ogdensburg
Specimen size: 4.8 x 4.0 cm