mineral

Amethyst druzy quartz with calcite and gray matrix

Quartz, SiO₂ (amethyst variety), with probable calcite, CaCO₃

AI-generated identification · may be incorrect

Pale lavender, sparkly druzy quartz coating with vitreous luster; associated cream-colored blocky crystals likely calcite and gray chalcedony or host rock. Quartz hardness is 7, calcite 3; quartz has trigonal crystals and indistinct cleavage, while calcite has rhombohedral cleavage.

Identified September 12, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica- and carbonate-rich hydrothermal fluids filled a cavity or vug, depositing calcite and later amethyst quartz. The precise geological age and locality cannot be determined from the photograph.

Uses & applications

Used as a decorative mineral specimen, carving material, and occasional jewelry stone; druzy surfaces are mainly valued for display rather than durability. Calcite-bearing amethyst specimens are popular among collectors.

Geological facts

The purple color results from trace iron and irradiation in quartz. The pale color suggests relatively low coloration, and the crystal coating is druzy—many tiny quartz crystals covering a surface.

Field identification & locations

Identify it by testing for quartz hardness and examining the purple quartz sparkle; calcite can be scratched with a steel point and may effervesce in dilute acid. Common sources include Brazil, Uruguay, Mexico, and Morocco, but locality is not identifiable here.