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Chalcedony

Carnelian

Orange to reddish-orange, colored by iron oxides

Brown Orange Red-Orange
Optical properties

Optical characteristics

Ref. index
1.53 – 1.543
Birefringence
0.004
Luster
Waxy
Pleochroism
None None.
Fluorescence
Inert.
Origins

Source localities

Brazil Brazil: Minas Gerais / Paraíba / Bahia
Significant

Major source for beryl, tourmaline, quartz, topaz, chrysoberyl and rare minerals.

20% est. supply
Iran Iran: Nishapur / Khorasan
Major ★ Top Source

Classic Persian turquoise source; also a source of carnelian and agate.

15% est. supply
India India: Rajasthan / Odisha / Karnataka
Significant

Historic and modern source for garnet, moonstone, corundum and other gems.

40% est. supply
Uruguay Uruguay: Artigas amethyst fields
Commercial

Known for amethyst geodes and quartz; also produces agate and carnelian.

15% est. supply
United States USA: major gem fields
Commercial

Diverse sources for turquoise, tourmaline, opal, sapphire, topaz, red beryl and rare minerals.

10% est. supply
Treatments

Enhancement & treatment

Heat Heat Treatment, Quartz Heating is common in commercial citrine and other quartz colors. It changes color centers… Color Enhancement Dyeing Dyeing artificially improves color in porous or fractured materials. Durability varies and disclosure is…
Inclusions

Inclusions & features

Zoning Color Zoning Under 10x loupe in immersion: bands or patches of deeper or lighter color arranged… Clouds Pinpoint Clouds Under 10x loupe: concentrations of extremely tiny bright dots that individually are too small…
Identification

Instruments used

10x Loupe Your most-used instrument, start every examination here Refractometer Measures refractive index, the backbone of gem identification High CRI Penlight Tiny concentrated white spot for field checks, inclusions, fire, and fractures UV Lamp, Long Wave and Short Wave Fluorescence exposes treatments, synthetics, and origin