Azurite

Blue azurite replacing calcite in franklinite-willemite-calcite ore.  In this specimen, azurite is nearly absent from the calcite-poor ore in the center but is abundantly present above and below, where the rock contained much more calcite.  The azurite lines cleavage surfaces and fractures in the calcite and in places has replaced that mineral entirely.  The host rock is altered ore consisting of magnetic franklinite, calcite, and a translucent brown mineral in abundant, rounded grains, possibly tephroite or perhaps willemite so thoroughly serpentinized that all trace of its original fluorescence is lost.  The calcite, however, still fluoresces brightly.  Ex specimen JEM 2484 of John MacDonald, and probably acquired by him in December 1960.  Later specimen ERV-448 of Earl Verbeek, who in October 1986 purchased it from Jim Kaufmann and in 2024 donated it to the Franklin Mineral Museum, where it remains as their specimen FMM-3219.

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