goethite (w. cuprite, dolomite and malachite)

Part of a reniform mass of concentrically zoned goethite. Certain surfaces of the goethite are peppered with microcrystals of lustrous blood-red cuprite and / or malachite.

On the broken (zoned) surfaces (Exhibit 2), flattened groups (to 2 mm) of cuprite with individual crystallites to 0.5 mm are present.

On the yellow convex outer surface (exhibits 1 and 3), slightly larger individual euhedral cuprite crystals (to 0.75 mm) are present and altered to malachite to varying degrees. On the blue-green outer surface (Exhibit 3), the colour is due to malachite in tiny coalescent sub-spherical aggregates that may (!) be after cuprite (?). This same blue-green surface is richly peppered with individual curved rhombs of colourless to pale-tan coloured dolomite crystals (typically circa 1 mm).

Mark Feinglos bought this specimen from Charlie Key in June 1995; Key’s accompanying label (Exhibit 4) attributes it to 45 Level.

cuprite; dolomite; malachite