Esfalerita
Esfalerita is a mineral with formula ZnS, in the Sulfuros group. This specimen comes from Mina Troya, Mutiloa, Gipuzkoa, Euskadi, España and joined the Terrium collection in 1989.
Description
Floater plate of honey-caramel sphalerite aggregates with high lustre and well-defined faces, partially coated by white dolomite. Fully crystallised on both sides, with no breaks or contact points.
History of this specimen
Antonio Barahona got it in 1989, before the final closure, directly from miners, when good specimens could still be obtained if you knew whom to talk to. It remained with him until it came into my hands.
About Esfalerita
Sphalerite is the principal ore mineral of zinc, often iron-rich, which imparts darker tones. In well-crystallised specimens it can reach gem quality and a very high lustre. At Troya it is frequently associated with white dolomite.
About the locality
A historic European reference locality. The last major deposit discovered in the Basque Country, in 1972. Worked by Exminesa between 1986 and 1993, when a collapse forced its closure. It was an underground lead–zinc gallery over one kilometre long. Its large geodes (even several cubic metres) produced some of the best sphalerites from Spain, prized for their transparency and honey–cognac colour. Closed and flooded since 2009, its settling pond (slimes) has recovered fully and is now an ornithological enclave.
Technical data
- Catalogue No.
- 0341
- Composition
- ZnS
- Name
- Esfalerita
- Group
- Sulfuros
- Category
- Cupidium
- Associations
- dolomita
- Mine
- Mina Troya
- District / Municipality
- Mutiloa
- Province
- Gipuzkoa
- Region
- Euskadi
- Country
- España
- Size (cm)
- 7 x 4 x 3
- Weight
- 93.4 g
- Acquired
- 1989
- Ex-collection
- Antonio Barahona
- Etymology
- The name of this mineral is a fossilised miners' insult. Early German miners named it "Blende" (from the verb 'blenden', to deceive) because its lustre promised good metals (lead or silver), but when smelted to extract value… nothing good came out. Official science kept the slight: in 1847 it was named sphalerite, from the Greek 'sphaleros', which literally means 'treacherous!'.
- Quality
- Top
- Value trend
- Al alza
Related specimens
- Abellaíta — España
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Acantita (Paramórfica tras Argentita) — Marruecos
- Aerenita — España
- Aerinita (fibrosa) — España
- Analcima — España