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Seraphinite disc
While I covered this lovely green mineral before (see http://on.fb.me/1Hl3vnM), this wonderful 15 cm across natural aggregate of fibrous crystals is a stunner. Formed by the alteration of limestones by hot brines spat out of a cooling iron rich granite that was stewing in its own juices after reaching its buoyancy point in the crust of the Earth in one specific Siberian locality, it was named after the supposedly delicately textured wing feathers of the highest order of angels. The fibres could be cut into catseye stones, but it would ruin a wonderful mineral specimen, something I'm generally against (though for the record, I have nothing against cutting river rolled pebbles and angular cleavage fragments, just lushly formed crystals)
Loz
Image credit: Carion Mineraux
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