New World Update 26 July 2022

26 July 2022

FOLLOWING last week’s extravaganza of British minerals we return to a world-wide selection this week featuring both the interesting and the aesthetic. A fair number of countries are featured including several from across Africa. This is where we’ll begin our review and first on the agenda is our old favourite, the famous Tsumeb mine in Namibia.

Now closed for over 20 years, the Tsumeb deposit found fame among mineralogists even before the mine was begun. The orebody outcropped at surface and had been recognised as a source of copper by local Bushmen probably for many hundreds of years. Exploration geologist Matthew Rogers first encountered the outcrop, subsequently named the Green Hill, on 21st January 1893 and wrote an account describing it as nothing like he had ever encountered before, or was likely to see again. The orebody was approximately 120 x 15 m in cross-section and reputedly stood 12 m above the surrounding land surface. Little did Rogers know the ore pipe descended to over 1000 m below ground level and would become one of the most iconic mineral localities ever known. We can only dream of being transported back in time to the Green Hill and enjoy a few days’ collecting. This would have made a good episode of The Time Tunnel (remember this TV series?), provided Doctors Newman (James Darren) and Phillips (Robert Colbert) remembered to take hammers and chisels with them! What a field trip that would have been!

We can’t supply you with a time machine, but we do have great examples of Zincolivenite and Galena from Tsumeb. Formerly named Zincian Olivenite, Zincolivenite forms the intermediate member in the Olivenite-Adamite solid solution series. Zincolivenite is now a recognised species and in this specimen forms beautiful gemmy, pseudo-octahedral crystals with acid lemon cores and bright leafy-emerald green face-edges. Such crystals completely cover an area of 4 x 2 cm at one end of the matrix.

Rather surprisingly, well crystallised Galena was fairly rare at Tsumeb, despite it being one of the world’s premier deposits containing the best-of-species of many much rarer minerals. This interesting small cabinet specimen contains numerous intergrown Galena crystals, typically of about 1 cm across and forming flattened triangular and hexagonal prisms with bevelled edges. The entire specimen is dusted with micro-sucrosic colourless Calcite crystals. The Galena forms flattened, triangular, spinel twins, often displaying ragged linear ridges over the crystal faces, typical of Tsumeb Galena.

Also from Africa, take a look at a delightful nodular Malachite from the L'Etoile du Congo mine (Star of Congo) in the Katanga Copper Crescent of the Democratic Republic of Congo. Two elongated emerald-green nodules measure up to 4.9 and 3.1 cm, the Malachite having a fine-granular texture with a satin lustre, making a lovely and most characteristic miniature. Moving down to the Kalahari Manganese Field of South Africa, a showy pair of octagonal Hausmannite crystals display well against a matrix encrusted with pale pink, nicely crystallised Andradite Garnet, dusted with fine-sucrosic white Calcite.

One outstanding specimen well worthy of close scrutiny is a Rutile with Quartz and Chlorite from Ticino in Switzerland. The Rutile is a lustrous metallic reddish-bronze and occurs as rich carpets of reticulated acicular crystals coating and included within the Quartz crystals, some of the latter being developed to over 4 cm. This cabinet specimen is accompanied with an 'F.H. Butler, late Talling, Mineralogist' label, addressed '180, Brompton Road, London, S.W.' Francis Butler labels with this particular address (180) date between 1884 and 1887. This is an incredibly rich example of reticulated Rutile and is quite spectacular.

More rapidly mentioning some of our European specimens, we have a Calcite included with Boulangerite from Cavnic mine in Romania and two quite different specimens of Calcite with iridescent Pyrite from Príbram in the Czech Republic. And from Germany, a rich Native Bismuth from Schneeberg; Fluorite with Quartz from Erika mine at Säulnhof; oily green Pyromorphite crystals on Baryte from Heilige Dreifaltigkeit mine in Saxony and a beautiful miniature Baryte with golden honey terminations from the Pöhla-Tellerhäuser mine, also in Saxony.

Let’s end with two very different specimens from opposite sides of the globe. From Pasto Bueno in Peru, bright, metallic silver Galena crystals form multiple spinel twins of up to 2 cm with an infilling of dull, whitish-silver Marcasite between crystals. Scattered between these are glassy bundles of delicate colourless to milky white Baryte crystals. Then, finally to China and a subtly tinted green, lilac and colourless group of octahedral Fluorite crystals from the Xianghualing mine in Hunan Province. The distorted octahedrons produce a display of predominantly triangular faces (up to 5.5 cm), essentially colourless with lilac outer zones with pale, pastel peppermint green cores.

Over the summer holiday period we have set the total number of specimens in each update at 15 and will continue to offer a broad selection from both Britain and worldwide. Enjoy looking through today’s selection; there are many terrific specimens just waiting for you to discover! 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.

 

EAST COAST GEM, MINERAL & FOSSIL SHOW 2022

We return to West Springfield, Massachusetts for the East Coast Gem, Mineral & Fossil Show which takes place on Friday, August 12 through to Sunday, August 14. Admission for the show is $10.00 (Under 13 free with adult) and Crystal Classics will be located at space 129 in the shows retail section. Doors open 10am-6pm on Friday and Saturday and 10am-5pm for the Sunday.

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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, PT
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