Citrine Identification Guide

What Citrine Looks Like

Citrine is the yellow to golden-orange to brownish variety of quartz (SiO2), colored by traces of iron. Natural citrine is usually a pale lemon to honey-yellow, while much commercial "citrine" is heat-treated amethyst, which tends toward a deeper orange to reddish-brown ("Madeira") with possible whitish zoning. Luster is vitreous, and it is transparent to translucent. Crystals are the classic quartz six-sided prisms capped by pyramids; massive and geode material is common.

Step-by-Step Field ID Checklist

1. Note color. Lemon to golden yellow (natural) or rich orange-brown (often heat-treated amethyst).
2. Check crystal form. Hexagonal prisms with pointed terminations indicate quartz.
3. Test hardness. Mohs 7 — scratches glass and steel; not scratched by a knife.
4. Look for fracture. Conchoidal, glassy; no cleavage.
5. Check zoning. Heat-treated amethyst citrine often shows color concentrated near the tips and a slightly reddish/burnt orange tone; natural citrine color is more even and paler.
6. Feel the heft. Light (SG ~2.65).

Key Diagnostic Tests

• Hardness: 7.
• Cleavage: None; conchoidal fracture.
• Streak: White.
• Density: ~2.65 g/cm3.
• Optics: Doubly refractive (weak), uniaxial; quartz never shows strong facet doubling like citrine-colored topaz/zircon would differ on.
• Acid/magnetism: Inert; non-magnetic.

Common Look-Alikes and How to Tell Them Apart

• Heat-treated amethyst (sold as citrine): Same species (quartz) but tends to orange-red with color zoning at the points; true natural citrine is paler and more uniform. Both are real quartz.
• Yellow topaz: Harder (8), denser (~3.5), with one perfect basal cleavage; citrine has none and is lighter.
• Yellow sapphire: Much harder (9) and denser (~4.0).
• Yellow beryl (heliodor) / golden beryl: Slightly harder (7.5-8), different RI, hexagonal but with flat terminations more often.
• Glass / yellow YAG: Glass shows bubbles, single refraction, and a swirly conchoidal fracture; citrine is doubly refractive.

Where It Is Typically Found

Natural citrine is relatively uncommon and forms in granite pegmatites, hydrothermal veins, and quartz geodes. The leading sources are Brazil (Rio Grande do Sul, where amethyst geodes are also heat-treated to citrine), Bolivia (the Anahi mine, also famous for ametrine), Madagascar, Russia (the Urals), Spain, and Uruguay.

Field Tips and Common Mistakes

First settle whether you even have quartz: Mohs 7, conchoidal fracture with no cleavage, weak double refraction, and a density near 2.65 confirm the species and immediately separate citrine from topaz (cleavage, denser), sapphire (much harder), and beryl (harder). Once quartz is established, the next question is natural versus heat-treated, since most market citrine is baked amethyst. Tells of heat treatment include a burnt-orange or reddish "Madeira" tone, color concentrated near the crystal terminations, and whitish or zoned cores; natural citrine tends to be a paler, more even lemon-to-honey yellow. Note that heat-treated material is still genuine quartz, just enhanced, so the distinction is about origin, not authenticity. Watch for glass imitations in cheap jewelry: they are singly refractive, often contain gas bubbles, and may show molded swirl marks. Finally, do not confuse smoky-tinged or greenish "lemon quartz" trade names with classic golden citrine; check the actual hue under neutral daylight before deciding.