Cave Calcite (Aragonite) For Sale

Cave calcite (also called cave popcorn or coralloids) is not actually calcite, but aragonite. This mineral forms within caves, mines, and moist areas that are rich in limestone. Formations occur as stalactites and stalagmites, typically as botryoidal or feathery (‘Flos Ferri’) branches. Cave calcite appears in a variety of colors, ranging from clear to milky white and rusty oranges. These colors, in addition to their funky, tree-like formations, make cave calcite an exciting addition to any collection. Enjoy the sights of spelunking without going underground!

Note: The specimens we sell are extracted as a byproduct of large mining operations saving them from impending destruction, as opposed to being extracted from pristine cave systems.

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Aragonite

$5 - $895

How Does Cave Calcite Form?

Aragonite and calcite are both calcium carbonates with the same chemical formula (CaCO3), but different crystal structures and symmetries. As calcium carbonates, both have the tendency to form speleothems in limestone-rich environments like caves. For clarification, a speleothem is a geologic formation that occurs as carbonates build up through various types of depositing along the walls of cave systems.

Cave calcite forms underground from groundwater deposition. As water seeps through limestone and CO2 is lost over time, these minerals will precipitate into a residue that looks like bulbous masses encrusting a surface. Cave calcite may also form when groundwater evaporates, but will present as a more creamy white that resembles actual popcorn. While it often forms as stalactites and stalagmites, it can also form unique, branching, tree-like structures. These beautiful formations are sometimes known as ‘Floss Ferri’ (flowers of iron) and frostwork.

Where Is Cave Calcite Found?

As one might expect, cave calcite forms underground most often in cave systems, though it has been observed growing on concrete or man-made structures such as mines, car tunnels, and parking garages, where water has seeped through and then precipitated. Cave calcite can form in any cave made of limestone!

Most commercially available specimens are extracted while mining for other ores in limestone deposits. One of the best known examples is the Potosi Mine in Santa Eulalia, Mexico. The massive mine produces some really fascinating cave calcite formations. The mine is primarily worked for silver, lead, zinc, and copper. A characteristic feature of the ore deposits found within the Cretaceous limestones of Mexico is the presence of caves in close association with the ore.

In 1912, miners broke into the first underground cavern at the site and found amazing cave calcite formations. Additional caverns have been discovered over the decades during mining operations. Luckily, collectors have been able to recover some of this material before the caverns were subsequently destroyed by the mining operations.

CAVE CALCITE (ARAGONITE) FOR SALE

How Does Cave Calcite Form?

Where Is Cave Calcite Found?