Tumbled Blue Chalcedony
Quartz var. Chalcedony · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal/Hexagonal system; typically occurs in microcrystalline, cryptocrystalline, or massive habits.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with microcrystalline structure
Formation Process
Hydrothermal or sedimentary; forms at relatively low temperatures through the deposition of silica from water in cavities of other rocks.
About This Crystal
A smooth, tumbled stone with a deep, saturated blue-gray color. It exhibits a waxy to vitreous luster and is generally translucent to opaque in this thick tumbled form.
Physical Characteristics
Color: Deep blue to denim blue with a white streak. Cleavage: None. Fracture: Conchoidal. Specific Gravity: 2.60–2.64. Fluorescence: Often inert, but can show dull green under SW UV.
Optical Properties
Refractive Index: 1.530–1.544. Weak birefringence. Generally lacks pleochroism due to its cryptocrystalline aggregate nature.
Hardness & Durability
Origin Region
Namibia, Madagascar, Brazil, Turkey, and India; often found in volcanic cavities and sedimentary layers.
Hardness & Durability
Mohs Hardness: 6.5–7. Excellent toughness due to its interlocking crystal structure; highly durable for jewelry.
Care & Maintenance
Hardy stone; clean with warm soapy water and a soft brush. Avoid prolonged exposure to harsh chemicals or intense direct sunlight which can cause some color fading over years.
Rarity & Value
Relatively common, though high-quality 'lavender' or intense 'mojave' blue shades are more valued. Commonly treated via dyeing to enhance blue saturation.
Special Characteristics
Known for its waxy luster and occasional 'phantom' bands if the stone is thin or back-lit.
Lore & History
Historically used in jewelry by the Greeks and Romans. Traditionally associated with the throat chakra and believed in crystal lore to promote calm, communication, and mental flexibility.