Ore I want for Christmas is...
Photograph A: Sphalerite (ZnS) with colloform texture and galena (PbS).
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Sample: Botryoidal concretionary growth of sphalerite (ZnS) with galena (PbS)
Mine: Pomorzany, Poland Primary Commodity: Zinc (Zn), Lead (Pb) Deposit Type: Mississippi Valley-type (MVT).
Pssst! Did you know that the Museum’s ore collection
is 176 years old? It’s true. The
collection’s roots lie in the Museum of Practical Geology which was founded in 1838 by Sir Henry de la Bêche.
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Some 16,000 samples later, the collection preserves one of the best historical records for global mining activities. It is a hugely valuable resource for the economic geology community and, despite its age, the collection is still growing through research-based fieldtrips, consultancy work and donations.
A Polish beauty
The fine banding in the sample in photograph A is a great example of what geologists call ‘colloform texture’. What might surprise you is that the cream and light brown bands are both the same mineral: sphalerite (ZnS). Sphalerite is the main zinc bearing ore mineral at Pomorzany. Zinc is used in galvanising steel to prevent rusting (BGS, 2004). The large, angular and silvery mineral is galena (PbS) and this is the main lead bearing ore mineral at Pomorzany. Lead is primarily used in lead-acid storage batteries (USGS, 2011).
The sample was donated to the ore collection by the Museum’s Dr Chris Halls in 2014. By lodging material with the Museum’s ore collection, Dr Halls and other donors are preserving representative ore material for future generations of mineral explorers and researchers. Preserving the past, documenting the present in order to answer questions of the future is a big part of the ore collection’s purpose.
Visit window twenty to view another beautiful sample from the ore collection with colloform texture.
References
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A Polish beauty
The fine banding in the sample in photograph A is a great example of what geologists call ‘colloform texture’. What might surprise you is that the cream and light brown bands are both the same mineral: sphalerite (ZnS). Sphalerite is the main zinc bearing ore mineral at Pomorzany. Zinc is used in galvanising steel to prevent rusting (BGS, 2004). The large, angular and silvery mineral is galena (PbS) and this is the main lead bearing ore mineral at Pomorzany. Lead is primarily used in lead-acid storage batteries (USGS, 2011).
The sample was donated to the ore collection by the Museum’s Dr Chris Halls in 2014. By lodging material with the Museum’s ore collection, Dr Halls and other donors are preserving representative ore material for future generations of mineral explorers and researchers. Preserving the past, documenting the present in order to answer questions of the future is a big part of the ore collection’s purpose.
Visit window twenty to view another beautiful sample from the ore collection with colloform texture.
References
- British Geological Survey. 2004. Commodity Profile: Zinc. Mineral Profiles. pg.1
- United States Geological Survey. 2011. Lead. Minerals Yearbook. pg.4
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