2.7" Malachite and Calcite Association - Zacatecas, Mexico

 
This is a 2.7" wide malachite and calcite association that was collected from the Concepcion del Oro of Zacatecas, Mexico. The botryoidal malachite is composed of tightly packed acicular crystals.

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, a banded pattern can sometimes begin to take shape, which explains the rings in all shades of green that are 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 it's value as a decorative stone, it's rarely mined as a copper ore anymore.

Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.
FOR SALE
$25
DETAILS
SPECIES
Malachite & Calcite
LOCATION
Concepcion del Oro, Zacatecas, Mexico
SIZE
2.7" wide
CATEGORY
ITEM
#144226