mineral

Blue Quartz (Dumortierite Quartz)

Quartz (SiO2) with inclusions of Dumortierite (Al7(BO3)(SiO4)3O3)

Hardness: 7 on Mohs scale; Color: Indigo to sky blue; Luster: Vitreous (glassy) to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65 - 2.91.

Hardness: 7 on Mohs scale
Color: Indigo to sky blue
Luster: Vitreous (glassy) to waxy

Identified March 23, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Indigo to sky blue; Luster: Vitreous (glassy) to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65 - 2.91.

Formation & geological history

Formed in silica-rich hydrothermal veins or metamorphic environments where boron and aluminum are present. The blue color is often caused by fibrous inclusions of the mineral dumortierite embedded within the crystalline quartz structure.

Uses & applications

Used primarily in lapidary arts for cabochons, beads, and carvings. It is popular among crystal collectors and utilized in metaphysical jewelry.

Geological facts

Blue quartz is one of the rarer color varieties of quartz found in nature, compared to clear, rose, or amethyst. While most blue quartz derives its color from inclusions like dumortierite, some types found in Virginia (Catoctin formation) get their color from ilmenite or rutile inclusions.

Field identification & locations

Identify in the field by its distinct blue hue and high hardness (it will easily scratch glass). Common locations include Brazil, South Africa, Madagascar, and the eastern United States (Virginia and Pennsylvania). Look for a dense, waxy mass rather than clear crystals.

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