New Tsumeb Update 24 August 2021

24 August 2021

THIS week we return to Africa and specifically, Tsumeb, that most popular of mineral localities whose aesthetic and rare species populate collections around the world.

Although we mainly understand how elements have become concentrated throughout geological time to form such rich and mineralogically diverse ore deposits like Tsumeb, it remains a marvel of nature that such things are possible. The Tsumeb mine is amongst the ten greatest mineral localities in the world, others which immediately come to mind being Mont Saint Hilaire in Quebec, Franklin-Sterling Hill in New Jersey and Příbram in the Czech Republic. To produce hundreds of mineral species in one relatively tiny volume of the Earth’s crust not only requires sequences of concentration and alteration, but an original, readily available supply of all the required elements in the vicinity of the deposit. 44 elements make-up the mineral deposit at Tsumeb, that’s 48% of all known elements in the Earth (and universe!).

What elevates Tsumeb ever higher is the happy coincidence that so many of its minerals have had space in which to beautifully crystalise. Today’s selection of 21 specimens are all miniatures or smaller, the tiniest being a micromount of the very rare species Keyite. Let’s take a quick look through what you can then delve into deeper through the web links provided.

Our selection of carbonates include Aragonite, Azurite, Calcite, Cerussite, Dolomite, Malachite and Smithsonite. All old favourites they may be, but from Tsumeb there is always that something a little bit different. One of the Calcites displays sharp, colourless intergrown rhombic crystals to almost 1 cm developed over an olive to lime-green Mottramite matrix, one of Tsumeb’s many classic combinations. Another is a handsome ex-matrix Calcite crystal displaying a distinct hexagonal cross-section of alternating broad and narrow faces. With pure white prism faces and a slightly yellow-buff tinged termination, all faces have a fine coating of sucrosic micro-crystallised Calcite. A more unusual Dolomite is that of chalky-white stalactitic fingers to 5 cm forming a slightly splayed sub-parallel group with a crystallized outer surface. The specimen’s shape is like Mr Spock’s fingers doing that Vulcan sign thing in Star Trek, you know, the one where it’s difficult to separate your fingers!

What about the Keyite I hear you ask. Keyite is like hen’s teeth, not at all easy to come by. Admittedly this is only a tiny specimen, very tiny in fact, but the Keyite crystal is there amongst the green Zincolivenite and is priced at just $200. Tsumeb mine is type locality to this extremely rare copper-zinc-cadmium arsenate which was only named in the 1970’s after the American dealer Charles Locke Key who first offered the initial specimens of this then unknown blue species.

Another nice rarity is the zinc arsenite Leiteite, this named for Luís António Bravo Teixeira Leite, an amateur mineralogist who recognised its first occurrence. This nice example forms a tablet-like block of colourless laminar crystals creating silvery, highly lustrous surfaces with a micaceous texture.

Quartz pervades all the ore-bearing zones at Tsumeb, including the country rock, yet well crystallised specimens are few and far between. This terrific specimen features two intergrown, stubby, opaque milky Quartz crystals, one completely terminated and one part-terminated, both dusted with micro-crystalline light sage-green Mottramite.

Do look at some of our lovely thumbnails such as the Arsentsumebite and Zincolivenite and a beautifully crystallised miniature Azurite with milky-white Cerussite. The final item to highlight is a wonderful and quite different Mimetite. Yes, any collector of Tsumeb tends to have lots of Mimetite specimens, but this ex. matrix miniature comprises of lemon-tangerine coloured crystals up to 5.7 cm tall, very large for this species at the Tsumeb. The crystals have a micro-sucrosic textured white coating of Mimetite giving an aesthetic frosted appearance and where two crystals are broken to one side, exhibit hexagonal cross-sections of apricot orange. A lovely specimen indeed.

For all Tsumeb connoisseurs out there and for all who are stealthily being converted, there are many fascinating specimens today, albeit of a smaller size for your collection. When initial mining began at Tsumeb in 1893, no one could have imagined the mineralogical legacy this deposit would relinquish. We hope you enjoy perusing today’s picks and that something jumps out at you, that little something essential for your collection. PT

                                         

If you'd like to see a video of any of the specimens listed above then please contact us at orders@crystalclassics.co.uk and we'll be happy to assist you. We endeavour to respond to all enquires within 24 hours during weekdays, however at the weekend it might take us a little longer to respond.

 

DATES FOR YOUR DIARY

Crystal Classics, and our sister company UK Mining Ventures, will be in attendance at the following shows for the remainder of 2021:

SEPTEMBER 10-18
Colorado Mineral and Fossil Fall Show 2021
Crowne Plaza Denver Airport Convention Center 15500 E 40th Ave, Denver, CO 80239, USA

SEPTEMBER 16-19
Hardrock Summit 2021 - Evolution
Colorado Convention Center, Four Seasons Ballroom 700 14th St, Denver, CO 80202, USA

OCTOBER 9-10
The Bakewell Rock Exchange 2021
Lady Manners School, Bakewell, Derbyshire DE45 1JA, UK

OCTOBER 22-24
The Munich Show 2021
Exhibition Center Messe München, WEST Entrance, Munich, Germany

NOVEMBER 20
The Sussex Mineral & Fossil Show 2021
Haywards Heath College, Harlands Road, Haywards Heath, West Sussex RH16 1LT, UK

NOVEMBER 27
Crystal Classics Winter Open Day 2021
No.1, The Old Coach Yard, East Coker, Somerset BA22 9HY, UK

 

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MINERAL WISH LIST

We also offer an additional service that enables you, as our customer, to contact us via orders@crystalclassics.co.uk with your mineral wish list to enhance your current collection, but are unable to find the right specimens on our website. We have 1000's of specimens in our general stock that do not appear online.

Author: JH
Categories: Updates

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