Gemstones

Precious Stones

With reference to the Precious Stones Trade (PST) Act Chapter 21:06, “precious stones” are rough or uncut diamonds and emeralds. Local dealers have to be licensed by the Ministry of Mines and Mining Development through the issuance of Precious Stones Licences, to trade in precious stones as defined by the PST Act.

Diamond (C) is a crystalline material made of carbon atoms, in the cubic system. This is one of nature’s most admired minerals and gemstones. Occurrences in Zimbabwe are associated with kimberlitic and placer deposits. Zimbabwe is a signatory to the Kimberly Process Certification Scheme, therefore all rough diamond exports are accompanied by a Kimberly Process Certificate, issued by MMCZ. Other uses: Industrial (cutting tools/blades/saws/drill bits/ abrasives) Mine Locations: River Ranch Diamond Mine in Beitbridge, Murowa Diamond Mine in Zvishavane, Chiadzwa Diamond Fields in Marange District of Mutare and DTZ on Chimanimani. Availability: Zimbabwe currently produces over one million carats per year.

The gemstone is the green variety of beryl, coloured by chromium. The trademark Zimbabwean Sandawana emeralds are characteristically yellowish green with tremolite needles as inclusions. The Sandawana minerals maintain the lovely yellowish green colour even in the smallest of pieces and are mostly suited to watch and fine jewellery. Mine Locations: Mweza Range in Mberengwa, Hurungwe. Availability: Mostly in small stone sizes

Semi-Precious Stones

This gemstone is the purple to violet variety of quartz. The gemstones can be supplied in rough or polished form. Mine Location: Northern border areas Availability: Good quality material is limited.

This is a rare and valuable gemstone, which is emerald green in natural light and red in artificial incandescent light. The colour is attributed to presence of Chromium ions in the crystal structure of the gemstone. Mine Location: The famous Novello claims in Masvingo Availability: Clean material suitable for polishing is rare.

This is the blue or aqua variety of beryl. The bulk of Zimbabwe aquamarine production is pale to medium sky blue colour while a small percentage is bluish green in colour. The bluish green beryl can be heat treated to give the desirable colour of aquamarine. Mines Locations: Karoi (mainly the Mwami Mica fields), Mt Darwin and Mutoko in small scale workings Availability: Size – bulk of production in small stones (0.5g pieces in unpolished stones), bigger stones up to 2g pieces also available but in very small quantities.

Golden yellow variety of beryl. Mines Locations: see aquamarine Availability: see aquamarine

Colourless variety of beryl Mines Locations: see aquamarine Availability: see aquamarine

Chrysoberyl (BeAl2O4) mainly occurs in pegmatite, greisens and hydrothermal deposits. Common varieties of the mineral in Zimbabwe are transparent chrysoberyl, chrysoberyl cat's eye and alexandrite. The semi-precious varieties (transparent chrysoberyl and chrysoberyl cat's eye )usually occurs in golden yellow, yellowish green to brownish green shades. Chrysoberyl cat's eye also known as cymophane displays a phenomenon called chatoyancy (cat’s eye effect) Mine Location: Karoi-Hurungwe District in small scale workings Availability: Usually in small sizes less than a carat when cut and polished.

Iolite or cordierite sometimes referred to as water sapphire because of its resemblance to sapphire is found in deposits associated with pegmatites. Zimbabwean iolite has a saturated sapphire blue colour, is reasonably priced and is available in big quantities. Mine Location: Makuti (Northern part Zimbabwe) from small scale workings Availability: Readily available

Tourmaline occurs in wide range of colours. Varieties available in Zimbabwe are green, watermelon (rare in good qualities) blue and black tourmaline occurring in greisens and pegmatite deposits. All these varieties are mainly available in the pencil crystal form. Mine Location: Karoi – Hurungwe District from small scale workings Availability: Readily available especially the dark shades of green and black

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