Legrandite

Unknown Owner

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Legrandite is a rare zinc arsenate that occurs as a secondary mineral in the oxidized zones of arsenic-bearing and zinc-bearing deposits. At Tsumeb, the first, best and only fine Legrandite crystals were from the famous 'Zinc Pocket', 44 level in the third oxidation zone, found in 1992. The honey-colored crystals are remarkably prismatic and stout for the species, with the largest crystal in this tight cluster being thick and 1.4 cm across. The luster is fabulous, the color a saturation not seen in Mexican Legrandite; and the crystals are translucent. There are two other species associated with these very fine Legrandites. The few slender white crystals are Reinerite by a known association (see also our previous specimen: https://www.irocks.com/minerals/specimen/48286). We obtained this in the purchase of thumbnails from the collection of the legendary dealer, Charlie Key (Keyite, Ludlockite); and sold it to the Nelson's. Legrandite was unknown to Tsumeb until the discovery of the Zinc Pocket; however, Reinerite was described from Tsumeb in 1958 from lesser quality samples that are shamed by the large and eye-visible crystals here. The glassy, brownish micro crystals that cover much of the matrix could very well be Tsumcorite (we have not analyzed them, however). It is worth noting that Tsumeb is the TYPE LOCALITY for both of these rarities. On top of having some of Tsumeb's best Legrandites, the possible association of the Reinerite and Tsumcorite elevates the quality and desirability of this thumbnail. From the well-known Tsumeb-specific thumbnail collection of Dick and Mary Nelson, built mostly from 1980-2010. Laszlo Kupi photo.