gemstone

Blue Agate (Dyed)

Silicon Dioxide (Chalcedony), SiO2

Hardness of 6.5 to 7 on the Mohs scale, vibrant blue color due to artificial dying, waxy to vitreous luster, microcrystalline (cryptocrystalline) quartz structure, conchoidal fracture with no true cleavage, specific gravity of 2.58 to 2.64.

Identified July 30, 2026More gemstone →

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Physical properties

Formation & geological history

Agate forms primarily within cavities of volcanic and metamorphic rocks as silica-rich groundwater deposits microcrystalline quartz in concentric layers over millions of years. This particular specimen has been artificially dyed and tumbled to achieve its vibrant uniform blue appearance.

Uses & applications

Commonly used in lapidary arts, tumbled stones, jewelry making, decorative ornaments, and crystal healing specimens.

Geological facts

Natural blue agate exists, but bright, vivid blue stones like this are almost universally produced by soaking natural grey or white chalcedony in a dye solution, a practice dating back thousands of years to ancient Rome.

Field identification & locations

Easily identified by its hardness, conchoidal fracture, and waxy luster. However, unnatural vivid coloration or dye pooling in surface fractures indicates human treatment. Found worldwide where quartz and volcanic rocks are present.

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