Tennanite ps. Galena with Wulfenite and Dolomite

$6,500.00

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This is a large, interesting and eye-catching pseudomorph and combination piece from the famous Tsumeb Mine! Big, sooty gray-black tennantite pseudomorphs after cuboctahedral galena crystals are sprinkled with translucent brown-red wulfenite crystals and set on a contrasting background of off-white dolomite rhombohedrons and a red-brown hematite-stained matrix! The tennantite after galena pseudomorphs are clearly complex and represent 1 to 5 cm (2 inch!) octahedrons modified cube faces possibly accompanied by other forms and maybe even twins. The matte finish, charcoal gray pseudomorphs have an added bonus of at least three dozen lustrous, translucent, reddish brown, beveled edge crystals from 2 mm to 1 cm across and are largely restricted to the pseudomorphs! Groups of off-white, sharply formed, saddle-shaped dolomite crystals averaging about 5 mm in size are clustered between the tennantite-galena pseudomorphs. Paragenetically, the galena (a lead sulfide) formed first and then was subsequently replaced by tennantite (a copper-arsenic sulfide/sulfosalt) in a complex replacement involving the displacement of lead by copper and some sulfur by arsenic. The replacement roughly maintained the cubo-octahedral galena form. Dolomite (a calcium-magnesium carbonate) was then formed after, and/or maybe late in the replacement stage of galena in clusters, and crystallized in between the pseudomorphs. At the final stage, wulfenite (a lead molybdate) formed gracing the pseudomorphs, and only very few dolomite crystals. This is just a crazy interesting piece with an intricate chemical and mineralogical history - typical of Tsumeb and so few other places; and it's very attractive as well for what it is. The separated crystals on matrix, the color contrasts, and the size all elevate this to a significant Tsumeb piece. We sold this to Stretch Young in the early 2000s when we obtained part of the Willy Israel Collection. Willy had been helping famous South African dealer Clive Queit for decades, and selecting fine Tsumeb material in payment for the help. He acquired this in 1979. Illustrated in Collecting Pseudomorphs: The Changelings of Mineralogy (Mineralogical Record, Jan 2025) on page 95. Laszlo Kupi photo.