sedimentary (primary) with artificial modification

Dyed and Metallic Coated Agate Geode

Silicon Dioxide (SiO2) with titanium/gold vapor deposition coating

Hardness: 7 (Mohs scale), Color: Artificial purple/gold iridescent, Luster: Vitreous to metallic, Crystal Structure: Hexagonal (microcrystalline/cryptocrystalline), Cleavage: None/Conchoidal fracture.

Identified March 23, 2026More sedimentary (primary) with artificial modification →

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Physical properties

Formation & geological history

Formed in volcanic or sedimentary cavities where silica-rich groundwater deposited layers of microcrystalline quartz over thousands of years. The specimen shown has been industrially dyed and heat-treated with a vapor-deposition coating (often called 'Aura' coating).

Uses & applications

Primarily used for decorative purposes, metaphysical collecting, giftware, and inexpensive jewelry components.

Geological facts

Natural agates are rarely this vibrant; the intense purple and metallic golden iridescence are created in a laboratory by bonding metal vapors to the surface of the natural quartz crystals. This process is known as PVD (Physical Vapor Deposition).

Field identification & locations

Identify in the field by looking for rounded, nodular rocks that feel lighter than expected; however, the colors shown here do not occur in nature. Collectors look for the 'druzy' (small crystal) interior. Common sources include Brazil and Uruguay.

Other sedimentary (primary) with artificial modification specimens

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Aura Quartz

Titanium-coated Silicon Dioxide (SiO2)

mineral

Chert (specifically Flint or Gray Chert)

Silicon Dioxide (SiO2)

sedimentary

Chert (Arrowhead Preform or Point)

Chert (Microcrystalline Quartz, SiO2)

sedimentary

Concrete with Aggregate

Artificial Conglomerate (Cement and Aggregate)

sedimentary

Concrete / Conglomerate (Man-made)

Artificial Conglomerate (Cementitious Composite)

sedimentary

Painted Garden Rock (likely Granite or Limestone base)

Silicon Dioxide (SiO2) / Calcium Carbonate (CaCO3) based substrate with Acrylic/Enamel pigments

igneous or sedimentary (anthropogenic modification)