mineral

Amethyst Agate (Polished Point)

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 Mohs; Color: Purple, lavender, white, and translucent brown/gray; Luster: Vitreous (glassy); Crystal structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 Mohs
Color: Purple, lavender, white, and translucent brown/gray
Luster: Vitreous (glassy)

Identified March 23, 2026More mineral →

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Physical properties

Hardness: 7 Mohs; Color: Purple, lavender, white, and translucent brown/gray; Luster: Vitreous (glassy); Crystal structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Formation & geological history

Formed in volcanic cavities or geodes. The agate layers form first by silica-rich fluids lining the cavity, followed by the growth of amethyst crystals. Many specimens are found in basaltic rocks in Brazil and Uruguay, dating back to the Mesozoic era.

Uses & applications

Primarily used as decorative display pieces, lapidary art, jewelry, and for metaphysical collections. Large polished points are popular 'statement pieces' in home decor.

Geological facts

Amethyst gets its purple color from irradiation of iron impurities in the quartz. The specimen shown is a 'tower' or 'point' that has been mechanically cut and polished to emphasize both the raw crystal druse and the internal banded agate structure.

Field identification & locations

Identify by its six-sided crystal faces (if present), distinct purple hue, and lack of cleavage. In the field, look for volcanic geodes. For collectors, look for deep purple color 'saturation' and unique agate banding patterns.

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