Lansfordite
Lansfordite is a hydrated magnesium carbonate mineral with composition: MgCO3·5H2O.[2] Landsfordite was discovered in 1888 in a coal mine in Lansford, Pennsylvania. It crystallizes in the monoclinic system (space group P21/c[3]) and typically occurs as colorless to white prismatic crystals and stalactitic masses.[4] It is a soft mineral, Mohs hardness of 2.5, with a low specific gravity of 1.7. It is transparent to translucent with refractive indices of 1.46 to 1.51.[5] The mineral will effloresce at room temperature, producing nesquehonite.[6]
| Lansfordite | |
|---|---|
| General | |
| Category | Carbonates |
| Formula (repeating unit) | MgCO3·5H2O |
| IMA symbol | Lfd[1] |
| Strunz classification | 5/D.01-30 |
| Dana classification | 15.1.6.1 |
| Crystal system | Monoclinic |
| Space group | P21/c (No. 14) |
| Unit cell | a=7.3458 Å, b=7.6232 Å, c=12.4737 Å, β=101.722° |
| Identification | |
| Formula mass | 174.39 |
| Colour | Colourless, white after exposure |
| Crystal habit | Crystals, stalactites terminated by crystal faces, efflorescences, parallel growths. |
| Cleavage | Perfect, Distinct |
| Mohs scale hardness | 2.5 |
| Luster | Vitreous (if fresh) |
| Streak | White |
| Diaphaneity | Translucent, opaque after exposure |
| Specific gravity | 1.6 |
| Density | 1.6 |
| Birefringence | 0.042 |
References
- 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.
- "Lansfordite Mineral Data". www.webmineral.com. Retrieved 2021-02-15.
- Liu, B.N.; Zhou, X.T.; Cui, X.S.; Tang, J.G. (1990). "Synthesis of lansfordite MgCO3*5H2O and its crystal structure investigation". Science in China. B33: 1350–1356.
- "LANSFORDITE". euromin.w3sites.net. Retrieved 2021-02-15.
- "Lansfordite". www.mindat.org. Retrieved 2021-02-15.
- "Lansfordite" (PDF). Handbook of Mineralogy. Retrieved 15 February 2021.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.