Dyed Blue Agate Slice
Quartz (Chalcedony) var. Agate · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal symmetry (Microcrystalline/Cryptocrystalline); Habit: Banded, massive, geode, or nodule.
Mineral Group
Silicates (Tectosilicate), Quartz Group
Chemical Formula
SiO2 (Silicon Dioxide) with artificial coloring agents
Formation Process
Hydrothermal; formed by the deposition of silica-rich groundwater in the cavities (vugs) of volcanic rock.
About This Crystal
Thin cross-section slice of a geode showing concentric banding. Exhibits shades of bright teal to navy blue (artificial) with translucent grey-white areas. Luster is vitreous to waxy.
Physical Characteristics
Color: Dyed shades of blue/teal; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.60–2.65; Fluorescence: Often inert unless the dye reacts.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Optical Phenomenon: Translucency and banding (agating). Doubly refractive (aggregate).
Hardness & Durability
Origin Region
Rio Grande do Sul, Brazil (major source for slices); also Uruguay, India, and USA.
Hardness & Durability
Mohs Hardness: 6.5–7; Toughness: Very good; Stability: Generally stable but dyes can be sensitive to light and heat.
Care & Maintenance
Clean with warm soapy water; avoid ultrasonic or steam cleaners as they may affect the dye. Store away from direct sunlight to prevent fading of the blue color.
Rarity & Value
Common; Value is low to moderate. Factors include size, pattern, and quality of Polish. Artificially dyed specimens are inexpensive mass-market items.
Special Characteristics
Concentric banding, botryoidal growth patterns, and artificial color enhancement through chemical surface treatments (soaking in salts).
Lore & History
Historically used for amulets and hardstone carving since Ancient Greece. Traditionally associated with the Throat Chakra (blue variety) and believed to promote stability and calm.