“Langbeinite-553833,” Carlsbad Potash District, Eddy and Lea Counties, New Mexico, USA, by John Kygier. Public domain.
This material 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.
| Data | Value |
|---|---|
| Name | Langbeinite |
| Colors | Colorless, white, gray, yellowish, greenish, pinkish, violet. |
| Hardness | 3.5-4. |
| Fracture | Conchoidal |
| Cleavage | None |
| Stone Sizes | Colorless stones potentially up to 10-15 carats. Cabochons of any size. |
| Formula | K2Mg2(SO4)3. |
| Crystallography | Isometric. Crystals are rare; usually massive, bedded; in nodules. |
| Refractive Index | 1.536 |
| Birefringence | None. |
| Luminescence | Faint greenish white in LW (New Mexico). |
| Luminescence Present | Yes |
| Luminescence Type | Fluorescent, UV-Long |
| Pleochroism | None. |
| Optics | N = 1.536. |
| Luster | Vitreous. |
| Specific Gravity | 2.83 |
| Transparency | Transparent. |
Optics: N = 1.536.
Occurrence: Evaporite deposits from marine waters.
Saskatchewan, Canada; North Germany; Austria; India. Carlsbad, New Mexico: beds up to 7 feet thick.
Comments: This material 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.
Name: After A. Langbein of Leopoldshall, Austria.
IGS Newsletter
