QUARTZ VARIETY CHEMICAL COMPOSITION

🔬 Crystalline Quartz Varieties

These have visible crystal structures and are typically transparent to translucent. All share the base formula SiO₂ (Silicon Dioxide).

Variety	Chemical Composition	Notes
Clear Quartz	SiO₂	Pure quartz with no visible inclusions.
Amethyst	SiO₂ + Fe³⁺ (Iron)	Purple color from iron and natural irradiation.
Citrine	SiO₂ + Fe³⁺ (Iron)	Yellow-orange; often heat-treated amethyst.
Ametrine	SiO₂ + Fe³⁺	Natural blend of amethyst and citrine.
Smoky Quartz	SiO₂ + Al + irradiation	Brown-gray from aluminum and radiation exposure.
Milky Quartz	SiO₂ + fluid inclusions	White due to microscopic trapped fluids.
Morion	SiO₂ + Al + irradiation	Very dark smoky quartz.
Blue Quartz	SiO₂ + inclusions (e.g., dumortierite)	Blue hue from mineral inclusions.
Rose Quartz	SiO₂ + Ti, Mn, or Fe	Pink from trace titanium, manganese, or iron.
Herkimer Quartz	SiO₂	Double-terminated crystals; often contain inclusions.

🧬 Cryptocrystalline (Microcrystalline) Quartz

These have crystals too small to see without magnification. Still based on SiO₂, but often include impurities.

Variety	Chemical Composition	Notes
Chalcedony	SiO₂	General term for microcrystalline quartz.
Agate	SiO₂ + mineral banding	Banded chalcedony with colorful layers.
Onyx	SiO₂ + parallel banding	Typically black and white bands.
Carnelian	SiO₂ + Fe (Iron oxide)	Orange-red from iron impurities.
Jasper	SiO₂ + various impurities	Opaque and patterned; often includes clay or hematite.
Chert	SiO₂	Dense, dull-colored quartz in sedimentary rocks.
Flint	SiO₂	A variety of chert with waxy luster.

✨ Optical & Special Varieties

These show unique visual effects or contain inclusions. Still fundamentally SiO₂, with added minerals or structural quirks.

Variety	Chemical Composition	Notes
Tiger’s Eye	SiO₂ + crocidolite (fibrous)	Chatoyant effect from fibrous inclusions.
Hawk’s Eye	SiO₂ + crocidolite (blue)	Blue version of tiger’s eye.
Cat’s Eye Quartz	SiO₂ + fibrous inclusions	Reflective band like a cat’s eye.
Aventurine	SiO₂ + mica or hematite	Sparkly due to metallic inclusions.
Rutilated Quartz	SiO₂ + rutile (TiO₂)	Contains golden or silver needle-like rutile.
Tourmalinated Quartz	SiO₂ + tourmaline	Black tourmaline needles inside quartz.
Scepter Quartz	SiO₂	Crystal with a cap over a thinner stem.
Phantom Quartz	SiO₂ + internal growth layers	Shows outlines of earlier growth stages.

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