3.6" Sparkling Blue Botryoidal Smithsonite w/ Aurichalcite - Congo

Sparkling Blue Botryoidal Smithsonite w/ Aurichalcite - Congo #302224

This is a gorgeous, 3.6" wide sparkling botryoidal blue smithsonite formation with a vein of fibrous aurichalcite near one edge, collected from the Yanga Koubenza quarries in the Republic of the Congo (Brazzaville). A few pockets of fabulous blue smithsonite and aurichalcite were found in the summer of 2021. This specimen is a small part of that find!

It is accompanied by an acrylic display stand.

Smithsonite forms in earthy botryoidal masses, sometimes forming grape-like structures. It can be found as a secondary mineral in oxidation zones of zinc ore deposits, in some sedimentary deposits, and as an oxidation product of sphalerite. The general chemical formula of smithsonite is ZnCO3, however Fe (iron), Mg (magnesium), Ca (calcium), Cd (cadmium), Cu (copper), and Co (cobalt) can take the place of Zn (zinc). This potential for elemental variation results in smithsonite's wide variety of colors, including blue, green, yellow, orange, pink, purple, brown, gray, white, and colorless.

Aurichalcite (chemical formula (Zn,Cu)5(CO3)2(OH)6) is a secondary mineral that forms in the oxidation zones of copper and zinc ore deposits. It often forms as radiating, fuzzy-looking acicular blue-green crystals and linings along cavity walls.

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