Hemimorphite
Description
A white ore composed of hydrous Zinc silicate. Hemimorphite is a minor ore of zinc that occurs in zinc mines worldwide with significant deposits in Siberia, Romania, Sardinia, Slovenia, Belgium (Vieille Montagne), Germany (Aachen), Poland (Silesia), England (Derbyshire), Mexico (Durango), and the U.S. (Montana, New Jersey, Colorado, Pennsylvania). Until the mid 18th century, the name calamine was used for both zinc silicate and zinc carbonate (smithsonite) minerals since they are similar in appearance and often occur in the same rock. Once they were recognized as two distinct minerals and assigned separate names, the name calamine was retained to designate their admixtures. Hemimorphite was also called electric calamine in the U.S.
Synonyms and Related Terms
calamine; electric calamine; hydrous zinc silicate; hydrated zinc silicate
Physical and Chemical Properties
- Soluble in mineral acids. Insoluble in water.
- Orthorhombic system with thin tabular crystals or platy aggregates.
- Perfect cleavage in one direction.
- Fracture = uneven to subconchoidal.
- Luster = vitreous to dull.
- Streak = colorless
| Composition | Zn4Si2O7(OH)2-H2O |
|---|---|
| Mohs Hardness | 4.0 - 5.0 |
| Density | 3.4-3.5 g/ml |
| Refractive Index | 1.61; 1.62; 1.64 |
Resources and Citations
- Mineralogy Database: Hemimorphite
- Encyclopedia Britannica, http://www.britannica.com Comment: "hemimorphite." Accessed 5 Dec. 2004 .
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
- Wikipedia: http://en.wikipedia.org/wiki/Hemimorphite (accessed Sept. 2, 2005)