Bornite

Massive, dark blue to violet (tarnished) bornite with golden-yellow chalcopyrite on altered, franklinite-willemite-calcite ore from Franklin. Embedded within the bornite mass in several areas are small masses of a dark greenish-brown mineral in divergent sprays of nearly fibrous crystals. Probably this is aegirine; see Dunn (1995, p. 431). Both the willemite and the calcite within 2 cm or so of the bornite mass are nonfluorescent, but the base of the specimen preserves a bit of less-altered ore showing the normal bright yellow-green SW fluorescence of the willemite. The specimen is from the collection of John Quick Stevens, former mine captain at Franklin, and a collector of its minerals from about 1910 to about 1945. The Stevens collection eventually was acquired by Richard Hauck, then of Bloomfield, NJ, and in April 1985 was purchased by Earl R. Verbeek (his specimen ERV-245). Subsequently it was donated to the Franklin Mineral Museum and became their specimen FMM-2743.

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