Tuesday Update – Calcite

THIS week our updates focus on carbonate species: Calcite today and Smithsonite on Friday.

Calcite is one of the most common minerals on Earth, but when 99.9% of that is in limestone and chalk, that does not necessarily translate into plentiful fine crystals. Indeed, even though Calcite is known to crystallize into one of the most diverse ranges of crystal forms, finding specimens to demonstrate all of those is near impossible.

In fact, even for a species as abundant as Calcite, it is still possible with knowledge and experience, to match some crystallized specimens to specific localities on Earth, such are the subtle variations in crystal shapes, colours, internal inclusions and associated rock and mineral species between places. Just glancing through the specimens today highlights this, with iconic places such as Elmwood mine and Sweetwater mine jumping out.

However, today we have gone a little overboard with Calcite from one mine – Tsumeb. This is because, through the acquisition last year of several important Tsumeb-dominated collections we have assembled an important suite of remarkably well-crystallized Calcite from this most famous of localities. Often overlooked in favour of the exotic rarities for which Tsumeb mine justifiably has legendary status, its Calcite forms are remarkable too, and should be enjoyed as classics in their own right. Certainly, the Duftite and Mottramite-included Calcite crystals are already absolute classics, but the purer, larger crystals from Tsumeb should be appreciated too, for their magnificent sculptural displays.

For those interested in learning more about famous forms of Calcite from around the world, the Extra Lapis, No. 4, on Calcite is an extremely useful guide and available to buy in the book listings below (be quick though as we only have one copy available!).

See you again on Friday when we will replace calcium with zinc and delve into the world of Smithsonite.

Please note: Today's featured specimens are situated at both our US and UK showrooms.