mineral

Quartz Druzy on Agate

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Clear to white crystals with reddish-brown iron staining; Luster: Vitreous to waxy; Crystal structure: Hexagonal/trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Clear to white crystals with reddish-brown iron staining
Luster: Vitreous to waxy

Identified June 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from hydrothermal fluids in cavities or vugs of volcanic rocks. The 'druzy' refers to the tiny glittering crystals that formed on the surface of the underlying agate base during the cooling process.

Uses & applications

Used primarily in lapidary work, jewelry (pendants and rings), crystal healing collections, and as decorative display specimens.

Geological facts

The reddish-brown tint is caused by iron oxide (limonite or hematite) inclusions or coatings. Druzy crystals are highly prized for their natural sparkle which mimics the appearance of sugar or snow.

Field identification & locations

Identify by looking for a 'sugary' coating of tiny crystals over a microcrystalline base. It is common in areas with past volcanic activity like Brazil, Uruguay, and the Southwestern US. Use a streak test (white) and check for hardness to distinguish from softer calcite.