Esfalerita
Esfalerita is a mineral with formula ZnS, in the Sulfuros group. This specimen comes from Joplin Field, Tri-State Mining District, Jasper County, Missouri, Estados Unidos and joined the Terrium collection in 1974.
Description
Dominant black to brown sphalerite crystals, very lustrous, twinned and with pronounced striations. Among them are numerous small, well-formed, translucent ruby-jack crystals. Set on a silicified limestone matrix coated by a fine druse of pale grey, sugary quartz.
History of this specimen
From Joplin, USA, to Germany—straight into Otto Hoffmann's collection.
About Esfalerita
This typical Tri-State District association is a classic of North American collecting and is now very difficult to find at this quality. Joplin sphalerite is recognised by its well-formed crystals, often twinned and striated, in jet-black to dark brown tones with high lustre, accompanied by translucent ruby-jack crystals on silicified limestone matrices. For decades this style of specimen set the aesthetic standard for the species in the United States. It is classic material from a closed chapter of collecting.
About the locality
The Joplin Field, within the historic Tri-State District (Missouri–Kansas–Oklahoma), was one of the world's largest zinc and lead producing districts. Its mining activity ceased decades ago, in the mid-20th century. By the 1970s the pieces in circulation were already starting to be regarded as old classics.
Technical data
- Catalogue No.
- 0328
- Composition
- ZnS
- Name
- Esfalerita
- Group
- Sulfuros
- Category
- Cupidium
- Matrix
- Caliza silicificada
- Associations
- cuarzo
- Mine
- Joplin Field
- District / Municipality
- Tri-State Mining District
- Province
- Jasper County
- Region
- Missouri
- Country
- Estados Unidos
- Size (cm)
- 7 x 3.5 x 3.5
- Weight
- 94.9 g
- Acquired
- 1974
- Ex-collection
- Otto Hoffmann
- Etymology
- The name of this mineral is a fossilised miners' insult. Early German miners called it "Blende" (from the verb 'blenden', 'to deceive') because its lustre promised good metals (lead or silver), but when they smelted it no metal of value came out. Formal mineralogy kept the slight: in 1847 it was named sphalerite, from the Greek 'sphaleros', literally 'treacherous'. This piece shows why: it carries black sphalerite (marmatite) crystals that really look like lead.
- Quality
- Muy buena
- Value trend
- Al alza
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