Clinohedrite



Clinohedrite is a calcium zinc silicate hydrate mineral. Several modern analyses show that this mineral conforms to the end-member composition, with little substitution of other cations.
Clinohedrite is one of Franklin's more remarkable minerals, but is not found at Sterling Hill. It was first described by Penfield and Foote (1898, 1901) from the Parker Mine, and much information was added by Palache (1935). Unit-cell parameters were first determined by Strunz (1941).
The crystal structure of clinohedrite has been the subject of a number of investigations; these were by Nitikin and Belov (1966), Venetopoulos and Rentzeperis (1976), and Simonov et al. (1977a). Simonov et al. (1978) also pointed out a relationship to gerstmannite. Venetopoulos and Rentzeperis (1976) described clinohedrite as having (ZnSiO4) layers parallel and interlayered with layers of Ca octahedra, in which Ca is coordinated by 4 oxygen atoms and two water molecules.
Description
Clinohedrite occurs in superb crystals up to 1 cm, but most are smaller, occurring in millimeters. It also occurs as granular, fibrous, and platy aggregates and as splayed plumose arrays in veins. The crystals, of extremely complex and hemimorphic morphology, have been studied by Penfield and Foote (1898, 1901), and the morphological data was expanded and summarized in great detail by Palache (1935), who also presented numerous crystal drawings. Clinohedrite crystals are predominantly pinacoidal, pseudoprismatic, and domatic in habit. Many crystals appear wedge-shaped, having inclined faces; this characteristic prompted the name of the species. Additionally, crystal faces are commonly curved. The color varies from colorless to white to pink to light violet. The luster is vitreous on crystal faces and fracture surfaces and pearly on the perfect cleavage. The density is 3.33 g/cm3. The fluorescence in ultraviolet is orange in both shortwave and longwave, but is not wholly consistent; some rare specimens do not exhibit orange fluorescence. In general, shortwave fluorescence is more intense than longwave, but varies in intensity from assemblage to assemblage; some violetish specimens have a weaker, pinkish-orange fluorescence (some observations courtesy of Chet Lemanski). The duration of phosphorescence was measured by Millson and Millson (1950) and was found to be 175-288 hours. Clinohedrite is also strongly pyroelectric and triboluminescent.
It is commonly distinguished from other species using ultraviolet fluorescence, although wollastonite, pectolite, johnbaumite, and other minerals have a similar fluorescent response; specimens which are apparently non-fluorescent are best verified using optical, chemical, or X-ray methods.
Clinohedrite occurs in two principal types of assemblages at Franklin, although there are many exceptions; it is always a secondary mineral. It commonly occurs as thin films and coatings on and near hardystonite, Ca2ZnSi2O7, from which it has formed by direct hydrothermal alteration. It may form complete replacements of hardystonite. (Dunn, 1995)


 Location Found: Franklin (Type Locality)
     
 
 Year Discovered: 1898
     
 Formula: CaZn(SiO4) · H2O
 Essential Elements: Calcium, Hydrogen, Oxygen, Silicon, Zinc
 All Elements in Formula: Calcium, Hydrogen, Oxygen, Silicon, Zinc
     
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
     
Fluorescent Mineral Properties

 Shortwave UV light: Bright orange
 Mid wave UV light: Moderately weak orange
 Longwave UV light: Orange
 Additional Information: Phosphoresces orange, weakest fluorescence at mid-wave
     
 To find out more about this mineral at minDat's website, follow this link   Clinohedrite

     
 References:
Dunn, Pete J. (1995). Franklin and Sterling Hill New Jersey: the world's most magnificent mineral deposits. Franklin, NJ.: The Franklin-Ogdensburg Mineralogical Society. p.363

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.51


The Picking Table References
 PT Issue and PageDescription / Comment
V. 57, No. 2 - Fall 2016, pg. 15Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 1, Richard C. Bostwick - Clinohedrite
View IssueV. 45, No. 1 - Spring 2004, pg. 10The Art of Fluorescent Mineral Photography, With Special Attention to the Minerals of Franklin and Sterling Hill Photographing the More Popular Franklin and Sterling Hill Fluorescent Minerals - Clinohedrite
View IssueV. 37, No. 1 - Spring 1996, pg. 18Closest-Packed Mineral Structures of Franklin-Ogdensburg: Kepler's Gift of the Snowflake, Part two of two parts, Paul B. Moore - Clinohedrite
View IssueV. 36, No. 1 - Spring 1995, pg. 12Closest-Packing and Hydrogen Bonds in Minerals of the Franklin Marble, Paul B. Moore - Clinohedrite
View IssueV. 33, No. 2 - Fall 1992, pg. 10The Check List of Franklin-Sterling Hill Fluorescent Minerals - Clinohedrite (Fluorescent Info)
View IssueV. 18, No. 1 - March 1977, pg. 23The Fluorescent Minerals of Franklin and Sterling Hill, NJ by Richard C. Bostwick - Clinohedrite
View IssueV. 13, No. 2 - August 1972, pg. 12The Fluorescent Minerals of Franklin/Ogdensburg Area by Frank Z. Edwards - Clinohedrite (Fluorescent Info)
View IssueV. 9, No. 1 - February 1968, pg. 12The Exclusive Minerals of Franklin/Ogdensburg, N.J. (as of January 1968) by Frank Z. Edwards - Clinohedrite
     
Images

     
Clinohedrite, hardystonite, willemite, calcite from FranklinClinohedrite, hardystonite, willemite, calcite from Franklin under shortwave UV Light
Clinohedrite, minor hardystonite, willemite, calcite, and franklinite from Franklin, New Jersey. Visible plates and coatings of clinohedrite are rare. Photo by JVF
Clinohedrite from Franklin, New Jersey under shortwave UV light. The clinohedrite fluoresces bright orange, hardystonite violet blue, willemite green and the calcite just a couple of spots of red. Photo by JVF
Clinohedrite, hardystonite, willemite, calcite from Franklin under longwave UV Light
Clinohedrite from Franklin, New Jersey under longwave UV light. The clinohedrite fluoresces dull orange and willemite green. A strong longwave UV response (fluorescence) is uncommon. Photo by JVF


Clinohedrite, hardystonite, willemite, andradite garnet and franklinite from Franklin, NJClinohedrite, hardystonite, willemite, andradite garnet and franklinite from Franklin, NJ under shortwave UV Light
Clinohedrite, hardystonite, willemite, andradite garnet (brown) and franklinite (black) from Franklin, New Jersey. 5 3/4" x 4 1/4". From the collection of, and photo by Robert A. Boymistruk.
Clinohedrite, hardystonite, willemite, andradite garnet and franklinite from Franklin, NJ under shortwave UV light. The clinohedrite fluoresces bright orange, hardystonite violet blue, willemite green and the garnet and franklinite are non-fluorescent. 5 3/4" x 4 1/4". From the collection of, and photo by Robert A. Boymistruk.


Clinohedrite, hardystonite, willemite, diopside, andradite garnet and franklinite from Franklin, NJClinohedrite, hardystonite, willemite, diopside, andradite garnet and franklinite from Franklin, NJ under longwave UV Light
Clinohedrite, hardystonite, willemite (tan, white), diopside(tan, zinc-schefferite), andradite garnet (straw) and franklinite (black) from Franklin, New Jersey. 2 1/4" x 1 1/4". Photo by WP.
Clinohedrite, hardystonite, willemite, diopside, andradite garnet and franklinite from Franklin, NJ under longwave UV light. The clinohedrite fluoresces dark orange, hardystonite very weak violet, willemite green and the diopside, garnet and franklinite are non-fluorescent. 2 1/4" x 1 1/4". Photo by WP.
Clinohedrite, hardystonite, willemite, diopside, andradite garnet and franklinite from Franklin, NJ under shortwave UV Light
Clinohedrite, hardystonite, willemite, diopside, andradite garnet and franklinite from Franklin, NJ under shortwave UV light. The clinohedrite fluoresces bright orange, hardystonite violet blue, willemite green and the diopside, garnet and franklinite are non-fluorescent. 2 1/4" x 1 1/4". Photo by WP.


Clinohedrite, hardystonite, willemite and franklinite from Franklin, NJClinohedrite, hardystonite, willemite and franklinite from Franklin, NJ under longwave UV Light
Clinohedrite, hardystonite, willemite (green, white) and franklinite (black) from Franklin, New Jersey. 3" x 3 1/2". Photo by WP.
Clinohedrite, hardystonite, willemite and franklinite from Franklin, NJ under longwave UV light. The clinohedrite fluoresces weak light orange, hardystonite very weak violet, willemite green and the franklinite is non-fluorescent. 3" x 3 1/2". Photo by WP.
Clinohedrite, hardystonite, willemite and franklinite from Franklin, NJ under shortwave UV Light
Clinohedrite, hardystonite, willemite and franklinite from Franklin, NJ under shortwave UV light. The clinohedrite fluoresces orange, hardystonite violet, willemite green and the franklinite is non-fluorescent. 3" x 3 1/2". Photo by WP.


Amethystine clinohedrite crystals, hancockite, andradite, hendricksite, minor willemite, from Franklin, NJAmethystine clinohedrite crystals, hancockite, andradite, hendricksite, minor willemite, from Franklin, NJ under shortwave UV Light
Amethystine clinohedrite crystals (light violet to clear), hancockite (reddish brown), andradite (golden brown), hendricksite (black), and minor willemite, from Franklin, NJ. Field of view 2 1/4". From the collection of, and photo by Robert A. Boymistruk.
Amethystine clinohedrite crystals, hancockite, andradite, hendricksite, and minor willemite, from Franklin, NJ under shortwave UV light. Field of view 2 1/4". The clinohedrite fluoresces yellow-orange and the willemite green. From the collection of, and photo by Robert A. Boymistruk.







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