Vonsenite, Ludwigite (Var: Alumoludwigite), Calcite

Well formed, terminated short-prismatic crystals of black Vonsenite. It had appear as result of dissolution and redeposition of more former greenish Alumoludwigite from massive ludwigite-kotoite marbles. Alumoludvigite form long-prismatic crystals and acicular spherulites very similar to aegirine suns (one of them present in basement of the left Vonsenite crystal). Primary Calcite of the initial marble is yellowish and fine-grained, while the new formed, redeposited Calcite of later veinlet is snow-white and coarse-grained. Vonsenite crystals are riming this later Calcite veinlet. By the way, this is the best formed Vonsenite crystals which I had sometimes seen. FOV is ~3x3 cm. Pavel M. Kartashov collection and photo.

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Photo added: 5th Jun 2008