mineral

Druzy Quartz on Ironstone

Silicon Dioxide (SiO2) on Limonitic Ironstone

Hardness: 7 (Quartz coating) / 4-5.5 (Matrix); Color: Clear to white crystals on reddish-brown base; Luster: Vitreous to sparkling; Crystal structure: Hexagonal; Cleavage: None

Hardness: 7 (Quartz coating) / 4-5
Color: Clear to white crystals on reddish-brown base
Luster: Vitreous to sparkling

Identified May 23, 2026More mineral →

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Physical properties

Hardness: 7 (Quartz coating) / 4-5.5 (Matrix); Color: Clear to white crystals on reddish-brown base; Luster: Vitreous to sparkling; Crystal structure: Hexagonal; Cleavage: None

Formation & geological history

Formed through hydrothermal precipitation of silica-rich fluids into cavities or over existing mineral surfaces in sedimentary iron-rich environments. Common in secondary mineralization zones.

Uses & applications

Used primarily as decorative specimens for mineral collecting and occasionally for jewelry in its rough form.

Geological facts

The 'druzy' (or druse) effect is caused by a coating of tiny crystals that reflect light in many directions, creating a sugar-like sparkle. These often form in the hollows of geodes or as coatings on host rocks.

Field identification & locations

Identify by looking for a fine crystalline 'sugar' coating over a solid rock matrix. It is commonly found in desert environments or limestone/ironstone outcrops. Collectors should check for the hardness of the top layer with steel to confirm it's quartz.

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