dreamlike amethyst geode pair with a great shape and many white calcite crystals

A pair of amethyst geodes from Brazil with numerous white calcite crystals distributed over the amethyst crystal field as a later mineralization phase.

Calcite crystals in an amethyst geode form when carbonate-rich residual solutions circulate in the geode after the amethyst growth has completed, and calcite crystals crystallize at individual points.

Amethyst belongs to the quartz family and crystallizes in volcanic gas cavities within lava flows. The violet color is caused by tiny traces of iron in the crystal lattice under natural radiation over millennia.

What distinguishes this pair is the multitude of calcite crystals over the inner surface, which contrast the deep violet crystal field like white accents.

Calcite crystals are Mohs 3, significantly softer than amethyst (Mohs 7), and sensitive to acid. Special care must be taken during cleaning.

A collector's item of the highest class with didactic depth: two mineralization phases are concentrated in a single pair.