mineral

Botryoidal Chalcedony

Silicon Dioxide (SiO2)

Hardness: 6.5-7 Mohs; Color: White to grayish-cream; Luster: Waxy to vitreous; Crystal structure: Trigonal/Monoclinic (Cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: White to grayish-cream
Luster: Waxy to vitreous

Identified June 7, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: White to grayish-cream; Luster: Waxy to vitreous; Crystal structure: Trigonal/Monoclinic (Cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Formed by the precipitation of silica from aqueous solutions, often in cavities of volcanic rocks or within sedimentary limestone. This specific specimen exhibits a botryoidal (grape-like) growth habit.

Uses & applications

Used in ornamental carvings, gemstone cabochons, and as a sought-after specimen for mineral collectors.

Geological facts

Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. The word chalcedony comes from the Latin 'chalcedonius', derived from Chalcedon in Asia Minor.

Field identification & locations

Identify by its waxy luster, hardness (it will scratch glass), and bubbly, rounded 'botryoidal' surface texture. Common in desert regions, volcanic outcrops, and inside geodes.