Barylite is a barium beryllium silicate mineral. Microprobe analyses of Franklin material by this writer were published by Gaines and Bostwick (1993). The composition of barylite is remarkably uniform and conforms closely to the theoretical composition. Solid solution is quite limited; only Pb substitutes for Ba to any appreciable extent. Several representative analyses yielded SiO2 37.4, 37.2, BaO 45.9, 44.6, PbO 1.5, 2.6, with Be calculated at 15.5, 15.5, totals = 100.3 and 99.9
wt. percent. Spectrographic analysis by Northup and Lee (1940) showed 0.0x Mg and only traces of Mn, Fe, Al, Pb, Zn, and Sn, given in order of decreasing concentration.
Barylite was found at Franklin in 1929 and described by Palache and Bauer (1930). Additional discussion was given by Palache (1935), and local material was used for the determination of the unit-cell and space group by Smith (1956), as given above. The synthesis of barylite was reported by Ito and Frondel (1966); they also reported X-ray powder data for Franklin barylite. Barylite is not known from Sterling Hill.
Franklin barylite occurs in platy crystals, wholly enclosed in matrix; subparallel masses of crystals up to 10 cm are known. Some crystals are slightly curved and coated with serpentine. Barylite is colorless to gray or grayish white, with vitreous luster, two good cleavages, and a density of 4.07 g/cm3. The high hardness (7) is diagnostic. Barylite is difficult to identify by visual examination.
The fluorescence in ultraviolet is deep violet and is faint using commercially available lamps. The vivid fluorescence reported by Palache and Bauer (1930) is seen only under the older, iron-spark fluorescence-generating units, no longer in use and difficult to find except in the Franklin area. Barylite's fluorescence was long a subject of local controversy (Gaines and Bostwick, 1993). Many specimens of bright-blue-fluorescent margarosanite in microcline were misidentified as barylite between 1930 and 1990. A bluish-white thermoluminescence was noted by Northup and Lee (1940).
Barylite was first found on the picking table, and later was found in 960 pillar, 20 feet below the 400 level and 15 feet from the hanging wall, in the Franklin Mine. Palache and Bauer (1930) described barylite occurring with hedyphane, willemite, copper, brown and gray calcite, and white curved calcite. They noted that barylite is more or less brecciated and some is coated with thin films of serpentine. This is the only assemblage known to [Dunn]. This assemblage of copper, curved white calcite, and serpentine stringers and films is quite recognizable once seen and was described in excruciating and superb detail by Gaines and Bostwick (1993). Barylite is a rare mineral at Franklin. (Dunn, 1995)

 Location Found: Franklin
 Year Discovered: 1876
 Formula: Be2Ba(Si2O7)
 Essential Elements: Barium, Beryllium, Oxygen, Silicon
 All Elements in Formula: Barium, Beryllium, Oxygen, Silicon
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Fluorescent Mineral Properties

 Shortwave UV light: Moderately weak violet
 Additional Information: Brief phosphorescence, under modern filtered mercury-arc shortwave lamps, best seen under iron arc.
 To find out more about this mineral at minDat's website, follow this link   Barylite

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.407

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.44

The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 57, No. 2 - Fall 2016, pg. 13Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 1, Richard C. Bostwick - Barylite
View IssueV. 34, No. 2 - Fall 1993, pg. 22The Fluorescence of Barylite From Franklin, New Jersey
View IssueV. 33, No. 2 - Fall 1992, pg. 10The Check List of Franklin-Sterling Hill Fluorescent Minerals - Barylite (Fluorescent Info)
View IssueV. 14, No. 1 - February 1973, pg. 10Mineral Notes - Barylite (small article)
View IssueV. 13, No. 2 - August 1972, pg. 11The Fluorescent Minerals of Franklin/Ogdensburg Area by Frank Z. Edwards - Barylite (Fluorescent Info)
View IssueV. 10, No. 1 - February 1969, pg. 8Harvard Research on Franklin Minerals - Barylite
View IssueV. 7, No. 1 - February 1966, pg. 9Barylite
View IssueV. 4, No. 1 - February 1963, pg. 5Barylite
View IssueV. 1, No. 2 - June 1960, pg. 11Barylite (small article)
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