mineral

Purple Banded Agate

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 (Mohs); Color: Vivid purple and white concentric banding (often dyed); Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Vivid purple and white concentric banding (often dyed)
Luster: Vitreous to waxy

Identified May 2, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed in cavities (vugs) within volcanic rocks or ancient lavas. Silica-rich groundwater percolates through these cavities, depositing layers of chalcedony over thousands of years. Natural purple agate is rare; most bright purple specimens are agate dyed to enhance color.

Uses & applications

Extensively used in jewelry (pendants, beads), decorative ornaments, bookends, and as healing stones in metaphysical practices. Historically used for precision balances and mortars.

Geological facts

Agate is the state gemstone of several US states. The banding is often rhythmic and follows the contour of the cavity it grew in, creating unique 'fortification' patterns.

Field identification & locations

Identified by its distinctive parallel or concentric bands, translucency when held to light, and waxy luster. Commonly found in Brazil, Uruguay, and Lake Superior regions. Look for the 'orange peel' texture on unpolished surfaces.