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 1985.
Description
Fish-like outline, the largest sphalerite crystal serving as the eye. The lower left area rests on the surface. Troya paragenesis with dominant dolomite, speckled with sphalerite and dusted with pyrite. On the reverse, some siderite completes the assemblage.
History of this specimen
José Luis Mas bought it from a miner on a trip he made to Mutiloa. I know there is, let’s say, a sister piece, bought at the same time and in the same place but by someone else.
About Esfalerita
Zinc sulphide commonly with impurities. The colour variations of sphalerite reflect its chemistry: while trace elements such as mercury, copper or bismuth define its more vivid hues, iron is responsible for darkening it.
About the locality
Worked by Exminesa until an underground collapse halted operations in 1993, this mine became renowned for its monumental geodes. From its depths came some of the best sphalerites in Spain: crystals of exceptional transparency and sought-after "honey-cognac" tones. Today, silence fills its flooded galleries, leaving the former tailings pond as the last vestige of its lead–zinc past.
Technical data
- Catalogue No.
- 0633
- Composition
- ZnS
- Name
- Esfalerita
- Group
- Sulfuros
- Category
- Cupidium
- Matrix
- Roca oscura
- Associations
- dolomita cuarzo pirita
- Mine
- Mina Troya
- District / Municipality
- Mutiloa
- Province
- Gipuzkoa
- Region
- Euskadi
- Country
- España
- Size (cm)
- 13 x 6 x 4.5
- Weight
- 270 g
- Acquired
- 1985
- Ex-collection
- José Luis Mas > Aleydis Soliveres
- Etymology
- From the Greek "sphaleros" (σφαλερός), meaning 'deceptive' or 'treacherous'. It was named for its resemblance to galena, the principal lead ore, yet it yielded no lead, to the frustration of ancient miners.
- Quality
- Notable
- 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