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Name Origin | Langbeinite color stone gets its name from A. Langbein of Leopoldshall, Austria |
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Chemical Formula | potassium magnesium sulfate (K2Mg2(SO4)3 |
Color | Colorless, white, gray, yellowish, greenish, pinkish, violet |
Hardness | 3.5 - 4 on Mohs Scale |
Crystal System | Isometric. Crystals are rare; usually massive, bedded; in nodules. |
Cleavage | None. Fracture conchoidal. Brittle. |
Specific Gravity (SG) | 2.83 |
Pleochroism | None |
Luster | Vitreous |
Stone sizes |
Colorless stones potentially up to 10-15 carats. Cabochons of any size. |
Occurrence | Evaporite deposits from marine waters |
Note: Langbeinite was first described in 1891. It is nondescript and is cut solely as a curiosity. The gems are soft, pale colored, or colorless with no fire. Few cut stones have been reported, but this may be due to a lack of interest rather than a lack of suitable rough.