Mineral (Chalcedony/Quartz variety)
Agate (Dyed Blue)
SiO2 (Silicon Dioxide)
Hardness: 6.5-7 on Mohs scale. Color: Natural agates are generally grayish, white, or banded with earthy tones; this specimen is artificially dyed blue. Luster: Vitreous to waxy. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific gravity: 2.58-2.64.
- Hardness
- 6
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 on Mohs scale. Color: Natural agates are generally grayish, white, or banded with earthy tones; this specimen is artificially dyed blue. Luster: Vitreous to waxy. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific gravity: 2.58-2.64.
Formation & geological history
Formed through the deposition of silica from groundwater in cavities of igneous rocks, often filling voids created by trapped gas bubbles in volcanic activity. The banding results from episodic deposition. This specific piece was later cut, polished into a heart shape, and artificially dyed to achieve the vibrant blue color.
Uses & applications
Used primarily in lapidary arts, jewelry-making (as pendants or beads, given the drilled hole), and decorative items. Dyed agates are popular for their vivid colors in affordable jewelry.
Geological facts
Agate is historically one of the oldest healing stones. The practice of dyeing agate dates back to ancient Rome; because agate is somewhat porous, it readily accepts dyes, allowing for bright, unnatural colors like the blue seen here.
Field identification & locations
Identify by its waxy luster, hardness (will scratch glass), and characteristic banding. The unnatural, overly vibrant blue color is a clear indicator that the stone has been dyed. Commonly found worldwide, prominently in Brazil, Uruguay, and the USA. Collectors should note the dye when assessing.
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