Mexican Aragonite

In Stone Fossils Verified independent store

→

Approx. dimensions: 6.5" x 5" x 2.5" Aragonite is a common carbonate mineral. It is unfortunately often thought of as the poor cousin to calcite. But aragonite is an interesting an d attractive mineral in its own right. It forms interesting habits and can have a soft pretty color. Its modes of formation and relationship to calcite are both curious and intriguing. Aragonite is a polymorph of calcite, which means that it has the same chemistry as calcite but it has a different structure, and more importantly, different symmetry and crystal shapes. Aragonite's more compact structure is composed of triangular carbonate ion groups (CO3), with a carbon at the center of the triangle and the three oxygens at each corner. Unlike in calcite, the carbonate ions do not lie in a single plane pointing in the same direction. Instead they lie in two planes that point in opposite directions; destroying the trigonal symmetry that is characteristic of calcite's structure. Show more