Uraninite (Penetration Twin)
Miniature, 4.0 x 2.7 x 1.6 cm
Bancroft, Ontario, Canada

Emplaced in orange calcite is a lustrous, black, octahedral crystal of uraninite, .7 cm across which has been twinned and penetrated by another uraninite crystal. The color contrast is awesome! Sharp uraninites of this quality are extremely rare from Bancroft. Note this is not a Zinn piece, but somehow a George Elling collection rarity I let get mixed into this update.