mineral

Quartz crystal cluster, possibly iron-stained quartz

Quartz (silicon dioxide, SiO₂)

AI-generated identification · may be incorrect

Translucent to transparent pale gray/cream crystals with a vitreous luster and pointed prismatic faces; likely hardness 7 Mohs, no cleavage, conchoidal fracture, and specific gravity about 2.65. The yellow-brown coating may be iron oxides or associated host material.

Identified August 24, 2026More mineral →

Explore Quartz crystal cluster, possibly iron-stained quartz in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Quartz precipitates from silica-rich hydrothermal fluids in fractures and cavities, commonly forming geodes and crystal-lined veins. The photograph cannot establish its geological age; the Paris-region prior does not strongly support a local hydrothermal quartz source, so it may be transported or collected elsewhere.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, electronics, and construction aggregate; attractive crystal clusters are sold as decorative and collecting specimens. This small piece would generally have modest commercial value.

Geological facts

The pointed crystals indicate growth into an open cavity rather than ordinary massive quartz. A second specimen in the image also appears to be a pale quartz or carbonate cluster, but cannot be identified confidently from this view.

Field identification & locations

Look for six-sided prisms terminating in pyramidal points, glassy luster, and scratch resistance greater than ordinary steel. A steel knife should not scratch it; avoid confusing it with calcite, which is softer (Mohs 3) and commonly rhombohedral. Quartz is widespread worldwide, but this exact specimen’s locality cannot be determined visually.