New Carbonate Minerals Update 13 April 2021

13 April 2021

This week’s selections are based on chemical classifications and today it is carbonate minerals. A carbonate is defined as a salt of carbonic acid, formed when oxygen combines with carbon to form the ion CO3. Any time you see a CO3 in a mineral’s formula, then it is some type of carbonate.

Well known carbonates include Malachite, Azurite and Smithsonite, with that most recognisable probably being Calcite (CaCO3). There are a total of 231 known carbonate minerals, most are rare and obscure with many occurring only as micro-crystals and coloured smudges!

Our selection ranges from thumbnail to large cabinet specimens and we are sure you will find a good variety of quite amazing pieces to enjoy and choose from.

Beginning with Malachite, we have four very different specimens from Russia, China and the Democratic Republic of the Congo (DRC). Before the discovery of the huge deposits within the copper belt of central Africa, Russian Malachite was especially prized in early collections. We have a real beauty from the Middle Urals, with one side cut and polished displaying wonderful colour and banding. From the Shilu mine in China, a beautiful ball of concentrically grown velvety and knobbly Malachite which shimmers with a silky lustre. Mashamba West mine in the DRC is famous for its magnificent specimens of Primary Malachite and today’s example is certainly of museum quality. The term primary Malachite refers to Malachite occurring in its natural crystal habit which, strangely, is something not common in nature, as it commonly forms botryoidal masses and pseudomorphs. Finally, and again from the DRC, a wonderful and very well crystallised example of the strange occurrence of Baryte with Malachite from the Shangulowé copper mine.

Adding a daub of pink are three Rhodochrosites, all of very different colour and habit from Oppu mine in Japan; Uchucchacua mine in Peru and the N'Chwaning Mines of South Africa. Rhodochrosite is a manganese carbonate, MnCO3.

The iron (II) carbonate Siderite can form spectacular crystals, two examples of which we offer today. One classic is from St. Pierre de Message in France, composed of an aesthetic array of interlocking thin bladed pale buff crystals with crisp sharp edges. From Tazna mine in Bolivia, chunky lenticular Siderite crystals to 2.7 cm diameter densely cover a brecciated matrix. The Siderite is smoky-grey with attractive rusty-orange edges and is surrounded with complex golden Pyrite and Quartz crystals.

We have two beautiful specimens of the zinc carbonate Smithsonite. The first is from Broken Hill in New South Wales with lustrous translucent pastel peppermint micro-crystals forming drusy hillocks over a Cerussite and Goethite matrix. Jumping continents, take a look at a bright bubble-gum pink Smithsonite from Choix in Mexico. This forms smooth mammillary druses with a stunning silky lustre over a matrix of granular pinkish Smithsonite. The habit, colour and lustre are arresting!

There are many fine Calcites also to look at including specimens from José María Patoni in Mexico; Cavnic mine in Romania; a large cabinet specimen of stubby nail head Calcite from Broken Hill, Australia and a gorgeous Calcite, Baryte and Marcasite from the Příbram mining district in the Czech Republic.

Carbonates are often colourful minerals and make spectacular specimens. We certainly have many for you to study and enjoy today, possibly including one or two which would make terrific additions to your collection.

                                         

Can't find what you're looking for? Contact us at orders@crystalclassics.co.uk for any enquiries.

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.  

We will endeavour to respond to all email/telephone enquires within 24 hours during weekdays, however at the weekend it might take us a little longer to respond.

Author: JH
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