Lecontite (sodium ammonium sulfate dihydrate, with potassium substituting for some ammonium, typically about a fourth[2]) is a sulfate mineral with the formula (NH4,K)NaSO4·2H2O. It was found by John Lawrence LeConte in Las Piedras Cave in Honduras as a breakdown product of bat guano, including crystals up to an inch long[3] and identified as a separate mineral by W.J. Taylor in 1858.[4] As of 1963 most natural specimens came from the same cave.[5]
| Lecontite | |
|---|---|
| General | |
| Category | Sulfate mineral |
| Formula (repeating unit) | (NH4,K)NaSO4·2H2O |
| IMA symbol | Lcn[1] |
| Strunz classification | 7.CD.15 |
| Crystal system | Orthorhombic |
| Identification | |
| Color | Colorless |
| Cleavage | {011} Distinct [2] |
| Mohs scale hardness | 2–2.5 |
| Luster | Vitreous to dull |
| Streak | White |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 1.745 g/cc[3] |
| Density | 1.745 g/cc |
| Refractive index | nα = 1.440 nβ = 1.454 nγ = 1.455[3] |
| Birefringence | δ = 0.015[3] |
Lecontite can easily be synthesized by reacting ammonium sulfate with sodium sulfate in aqueous solution and crystallized.[6]
References
edit- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b "Lecontite Mineral Data". Webmineral. Retrieved 2022-04-15.
- ^ a b c d "Lecontite". Mindat.
- ^ Taylor, W.J. (1858). "Lecontite, a new mineral". American Journal of Science and Arts. 76: 273–274.
- ^ Faust, Robert J.; Bloss, F. Donald (1963). "X-ray study of lecontite". American Mineralogist. 48 (January–February): 180–188.
- ^ Shintyakov, Dmitry. "Sodium ammonium sulfate". DmiShin home, crystal growing collection. Retrieved 2022-04-15.