mineral

Quartz (Iris / Rainbow Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Colorless to milky translucent with internal rainbow reflections caused by micro-fractures; Luster: Vitreous to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Luster: Vitreous to greasy

Identified July 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms in a wide variety of geological environments, including pegmatites, hydrothermal veins, and metamorphic rocks. The rainbow flashes (iridescence) are produced by light interference along thin internal fracture planes within the quartz crystal structure.

Uses & applications

Popular as a gemstone, display specimen for mineral collectors, and widely used in metaphysical/healing practices. Standard quartz is used heavily in electronics (piezoelectric crystals) and glassmaking.

Geological facts

The rainbow effect in natural quartz crystals is called 'iris quartz' or 'rainbow quartz'. It occurs when stress or thermal shock creates microscopic cracks within the transparent crystal, splitting white light into spectral colors through refraction and interference.

Field identification & locations

Can be identified in the field by its hardness (scratches glass readily and cannot be scratched by a steel knife), lack of cleavage, conchoidal fracturing, and distinctive internal rainbow reflections under bright light. Quartz is found globally, including widespread hydrothermal deposits in East Africa.

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