1.45" Chatoyant Hemimorphite on Malachite & Chrysocolla - Congo

Hemimorphite is a basic hydrous zinc silicate with the chemical composition Zn4Si2O7(OH)2 · H2O. It earned its name from the Greek terms that best define its crystal structure. It has two different terminations on each side of the crystal, hence the inclusion of the greek terms "hemi", meaning half, and "morph", meaning shape. The crystal formations can range anywhere between a crystal druze or botryoidal formation to radiating acicular crystals and more. Hemimorphite has been found in shades of white, beige, light brown, and a bright, electric blue. It can also form as yellow and green crystals on rare occasions.

Prior to 1803, hemimorphite and smithsonite were thought to be the same mineral, called "calamine". However, further scientific research concluded that these were two distinct minerals.

About Malachite

Malachite is an intense green copper-based mineral that can be found in a wide variety of forms. Malachite can grow in botryoidal masses, stalactitic formations, and reniform formations, typically as a tight cluster of fanning fibrous needles that make up a seemingly solid mass. As layers continue to stack during formation, banded patterns can sometimes begin to take shape, explaining the rings in all shades of green seen on most polished malachite specimens.

Malachite results from the weathering of other copper ores, and is very often found associated with other copper-based minerals such as azurite and chrysocolla. It can be found in copper deposits around the world, but the Democratic Republic of the Congo is the primary source for polished malachite and mineral specimens.

Malachite has been prized since ancient times, first as a utilitarian copper ore, then as an ornamental stone. Due to its value as a decorative stone, it is rarely mined as a copper ore anymore.

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 can also 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 bluish-green, bright green, light blue, to even sometimes multicolored specimens depending on the atmosphere present during formation.