3.3" Polished Malachite & Chrysocolla Slab - Congo

This is a beautiful, hand-polished slab of high grade botryoidal malachite and chrysocolla, mined in the Congo. The lapidary work is very nice, and allows for the great, natural botryoidal patterns in the minerals to be seen. This makes for an interesting and beautiful display piece.

Chrysocolla is a basic copper silicate that typically forms as a pseudomorph following other copper based minerals. The chemical formula is considered undetermined due to the varying substitutions of elements and water content in its chemical structure. However, there is a form of chrysocolla with an identifiable chemical formula of Cu2H2Si2O5(OH)4, that can be found in microcrystals.

Regularly, chrysocolla will form as botryoidal lumps and spheres, rarely forming visible crystals. It's also been known to form in both solid and fibrous veins, over fibrous minerals and in crusts. Known for its sharp and vibrant coloring, chrysocolla can display a wide variety of colors such as blueish-green, bright green, light blue to even sometimes multicolored specimens, depending on the atmosphere present during formation.

Malachite is a dark green, copper based mineral with the formula Cu2CO3(OH)2. It often forms botryoidal masses in fractures deep underground where the water table or hydrothermal fluids provide the means for chemical precipitation. It rarely forms crystals and it is often associated with another copper based mineral azurite. It was used as a mineral pigment in green paints from antiquity until about 1800.
Malachite & Chrysocolla
Katanga Province, Congo
3.3" wide, .26" thick