Rock Identifier
Dyed Blue Agate (Slab) (Agate (Variety of Chalcedony/Microcrystalline Quartz), SiO2) — mineral
mineral

Dyed Blue Agate (Slab)

Agate (Variety of Chalcedony/Microcrystalline Quartz), SiO2

Hardness: 6.5-7 on Mohs scale. Color: Deep navy blue (artificially dyed). Luster: Vitreous to waxy when polished. Crystal structure: Hexagonal (trigonal) microcrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

Hardness
6
Color
Deep navy blue (artificially dyed)
Luster
Vitreous to waxy when polished
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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Deep navy blue (artificially dyed). Luster: Vitreous to waxy when polished. Crystal structure: Hexagonal (trigonal) microcrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

Formation & geological history

Formed as nodules in volcanic rocks or ancient lavas, where silica-rich groundwater fills cavities (vesicles). Agate deposition can take millions of years, often occurring in layers. This specific specimen has been sliced and chemically dyed.

Uses & applications

Used primarily for decorative purposes, coasters, jewelry (pendants, beads), and metaphysical lapidary tools. Historically used for hardstone carvings.

Geological facts

Natural blue agate (like Blue Lace Agate) is typically a pale, milky lavender-blue. This specimen's intense, uniform navy color indicates it has been 'imbued' or dyed, a practice dating back to Ancient Rome using various metal salts.

Field identification & locations

Identify in the field by its translucent edges, waxy luster, and concentric banding (though banding is faint in dark dyed specimens). Commonly found in Brazil, Uruguay, and India. It will feel cool to the touch and cannot be scratched by a steel knife.

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