mineral

Blue Chalcedony

Silicon Dioxide (SiO2)

Hardness: 6.5–7 on Mohs scale. Color: Pale blue, lavender-blue, or grey-blue. Luster: Vitreous to waxy. Crystal structure: Trigonal (cryptocrystalline). Cleavage: None. Specific gravity: 2.58–2.64.

Hardness: 6
Color: Pale blue, lavender-blue, or grey-blue
Luster: Vitreous to waxy

Identified April 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed from watery, silica-rich solutions at low temperatures, typically in volcanic cavities (vugs) or within sedimentary environments. They accumulate in layers through the slow precipitation of microscopic quartz crystals.

Uses & applications

Commonly used in jewelry as cabochons, carvings, beads, and as decorative ornamental stones. High-quality specimens are popular for metaphysical collecting.

Geological facts

Chalcedony is a cryptocrystalline variety of quartz, meaning its crystals are too small to be seen with a standard microscope. Blue Chalcedony is often called 'The Speaker's Stone' in holistic circles.

Field identification & locations

Identified by its waxy luster and blue-to-grey translucency. It is commonly found in Turkey, Namibia, India, and the United States (Oregon/California). In the field, look for botryoidal (grape-like) habits or smooth nodules.