Localities
Olemina is a curator of fine mineral specimens. The Journal collects what we’ve learned about provenance, care and the localities that define each species — written to help you buy, keep and live with them.
Topaz Specimens: Imperial, Blue and Colourless Crystals
Topaz specimens range from prized orange-pink imperial crystals from Ouro Preto, Brazil, to natural pale blue, colourless and rare Pakistani pink material, though most vivid blue topaz sold…
Emerald Specimens: Beryl in Matrix and What Drives Value
Emerald specimens pair chromium-green beryl crystals with calcite, pyrite or schist matrix from Muzo, Chivor, Kagem and beyond — how locality, treatment and crystal form determine what a…
Wulfenite Specimens: A Collector’s Guide to Colour and Locality
Wulfenite specimens showcase orange-red tabular and pyramidal crystals from Red Cloud Mine, Los Lamentos, San Francisco Mine and Mibladen — each locality distinct, each prized crystal astonishingly fragile.…
Vanadinite Specimens: Morocco’s Red Crystals
Vanadinite specimens from Morocco's Mibladen district show brilliant red-orange hexagonal crystals on barite, but their softness, light sensitivity and fragile hopper crystals demand careful handling — here's how…
Rhodochrosite Specimens: A Collector’s Guide to Colour, Form and Locality
A collector's guide to rhodochrosite specimens: raspberry-to-rose-red manganese carbonate, its crystal forms and colour, the localities that define the market — Sweet Home, N'Chwaning, Capillitas, Wutong — plus…
Aquamarine Specimens: Gem Crystals for the Cabinet
Aquamarine is gem-blue beryl prized for transparent, well-terminated hexagonal crystals with even colour. Fine specimens come from Pakistan's Shigar Valley and Brazil, judged on clarity, termination and honestly…
Pyrite Specimens: Why ‘Fool’s Gold’ Is a Serious Collectible
Pyrite forms mirror-bright cubes and complex pyritohedra prized for their geometric precision. Spain's Navajón sets the world standard, while honest grading, correct identification and humidity control protect a…
Malachite Specimens: Banding, Botryoidal Form and Care
Our malachite specimen guide covers banding, botryoidal form and the soft copper carbonate's care needs, from DR Congo's Katanga Copper Crescent to the historic Ural malachite of Russia's…
Azurite Specimens: The Deepest Blue in the Mineral World
Our azurite specimen guide explains why this copper carbonate delivers mineralogy's deepest blue, how to judge crystal form and lustre, and why classic sources like Tsumeb and Milpillas…
Tourmaline Specimens: Reading Colour, Form and Origin
Our tourmaline specimen guide breaks down colour, bi-colour zoning and locality, from Brazil's Minas Gerais to Pakistan, Nigeria and Mozambique, so collectors can judge condition, termination and value…
Collecting Fluorite: Why Yaogangxian Sets the Standard
Fluorite is loved for its glassy cubes, wide colour range and natural zoning. China's Yaogangxian mine sets the modern benchmark for colour, clarity and crystal integrity, all working…
Amethyst Specimens: A Collector’s Guide to Colour, Locality and Value
Fine amethyst is judged on deep, even colour, sharp undamaged crystals, natural zoning and a verified locality, not size. Brazil, Uruguay, Zambia and Namibia each produce distinctive, recognisable…