Hemimorfita
Hemimorfita is a mineral with formula Zn₄Si₂O₇(OH)₂·H₂O, in the Silicatos group. This specimen comes from Mina Ojuela, Mapimí, Durango, México and joined the Terrium collection in 1980.
Description
Cavity in a ferruginous matrix lined with interlaced, transparent hemimorphite crystals with good lustre. It has small yellow bow-tie mimetite aggregates that can be enjoyed with a field loupe.
About Hemimorfita
A hydrated zinc hydroxysilicate, hemimorphite is a typical secondary mineral of the oxidised zones of zinc deposits, and at Mapimí it occurs in cavities lined with colourless, glassy crystals like this. Mimetite occurs as small yellow bow‑ties in association. It is an aesthetic and representative association for this historic mine.
About the locality
Ojuela Mine, now inactive, was one of the world’s major producers of secondary minerals. Its mining history dates to the 16th century, and for decades its workings yielded exceptional specimens of adamite, hemimorphite, mimetite and aurichalcite. Today material is collected only on dumps and in areas accessible to amateur collectors.
Technical data
- Catalogue No.
- 0047
- Composition
- Zn₄Si₂O₇(OH)₂·H₂O
- Name
- Hemimorfita
- Group
- Silicatos
- Category
- Cavella
- Matrix
- Goethita-limonita
- Associations
- mimetita
- Mine
- Mina Ojuela
- District / Municipality
- Mapimí
- Region
- Durango
- Country
- México
- Size (cm)
- 8.5 x 6 x 3
- Acquired
- 1980
- Ex-collection
- E. Nicolau
- Etymology
- The name "hemimorphite" comes from the Greek "hemi" ("half") and "morphe" ("form"), in allusion to the unequal development of the ends of the crystal. The name "mimetite" derives from the Greek "mimetes" ("imitator"), for its similarity to pyromorphite.
- Quality
- Notable
- Value trend
- Al alza