Pair of Amethyst Geodes in Best Color and Special Shape from Uruguay with Four-Pointed Calcite Crystal

An amethyst geode pair from Uruguay, in which a remarkable four-pointed calcite crystal grows out of the violet inner lining. A rare mineral constellation with clear crystallographic educational value.

Four-pointed calcite scalenohedra are a growth variant of calcite, in which four symmetrically arranged scalenohedral pyramids grow from a common center. The geometric constellation only arises under specific solution and pressure conditions during carbonate crystallization.

The amethyst background crystallized in the early phase of the geode from silica-rich solutions. Only then did the calcium carbonate-bearing solution penetrate the remaining cavity and allow the calcite crystal to grow in its unusual four-pointed form.

Uruguayan amethysts from the Artigas Basin are considered premium material because of their particularly compact, dark violet coloration. Such specimens with prominent carbonate accompaniment are highly valued in the collector trade as two-mineral genesis pieces.

A collector's item with a visual focus on the calcite crystal, without neglecting the amethyst background.