
mineral
Heat-Treated Citrine (Amethyst)
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 (Mohs scale), Color: Amber, burnt orange, or brownish-red tips with a white milky base, Luster: Vitreous, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: Amber, burnt orange, or brownish-red tips with a white milky base, Luster: Vitreous, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed as amethyst in volcanic geodes (typically in Brazil). The specimens are later artificially heated to high temperatures (approx. 450-550°C) which causes the iron impurities to change color from violet to orange-brown.
Uses & applications
Primarily used as decorative display pieces, in metaphysical collections, and occasionally as lower-cost gemstones for jewelry.
Geological facts
Natural citrine is quite rare and typically pale yellow; the majority of 'citrine' in the commercial market is actually heat-treated amethyst. When heated, the amethyst loses its purple hue and takes on the deep orange color seen here.
Field identification & locations
Identify by looking for a white, opaque base and concentrated dark orange or brownish tips. Natural citrine usually has a more uniform, honey-yellow color throughout the crystal and lacks the stark white base and burnt tips of heated specimens.
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