Seamanite (type locality) with Shigaite - image 1

Seamanite (type locality) with Shigaite - image 2

Seamanite (type locality) with Shigaite

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Here we have two very rare minerals from the old Homer iron mine near Iron River, Michigan. Seamanite is an ultra-rare hydroxylated manganese-borophosphate and Shigaite is a rare manganese-aluminum-sodium sulfate hydrate. This small cabinet piece has rich patches of Shigaite as tight clusters of less than 1 mm olive brown crystals on most surfaces and locally as excellent, isolated to loosely clustered, well-defined, hexagonal crystals of the species to almost 2 mm. The Seamanite occurs as thin, prismatic, almost fibrous, light tan, translucent crystals to 2 mm that are in direct association with the Shigaite and as outlying bundles of crystals on the Hematite matrix. Seamanite is largely restricted to a few mines in the Menominee Iron Range in Michigan and one locality in Australia and is incredibly rare at all known localities. Shigaite is also rare occurring at maybe a dozen localities worldwide. Shigaite is rarely available to collectors and we have never seen Seamanite available on the market!