Bultfonteinite, a calcium silicate hydroxide mineral, is rare at Franklin and is unknown from Sterling Hill. It occurs as colorless to white 1 mm crystals with vitreous luster. Partial analysis of these crystals yields SiO2 26.8, CaO 52.2, F 9.6 wt. %. Franklin bultfonteinite occurs as subparallel groupings of prismatic crystals in interstices between manganaxinite and calcite crystals in a light yellow rock composed of calcite, barite, manganaxinite, possible grossular, and sparse amounts of mica, andradite, hardystonite, and clinohedrite. (Dunn, 1995)

 Location Found: Franklin
 Year Discovered: 1932
 Formula: Ca2(HSiO4)F · H2O
 Essential Elements: Calcium, Fluorine, Hydrogen, Oxygen, Silicon
 All Elements in Formula: Calcium, Fluorine, Hydrogen, Oxygen, Silicon
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
 To find out more about this mineral at minDat's website, follow this link   Bultfonteinite

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

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