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Diamond · Variety of Diamond

Black Diamond

Opaque black; natural carbonado is polycrystalline, most market material is treated

Black
Optical properties

Optical characteristics

Ref. index
2.417
Luster
Adamantine to submetallic
Pleochroism
None None.
Fluorescence
Typically inert; treated black diamonds may show abnormal reaction.
Origins

Source localities

South Africa South Africa: Cullinan / Venetia
Legendary

Historic and important diamond source; also produces some carbonado material.

30% est. supply
Botswana Botswana: Jwaneng / Orapa
Premium

One of the most important diamond-producing countries.

20% est. supply
Brazil Brazil: Minas Gerais / Paraíba / Bahia
Significant

Major source for beryl, tourmaline, quartz, topaz, chrysoberyl and rare minerals; also source of natural carbonado.

50% est. supply
Treatments

Enhancement & treatment

Color Enhancement Irradiation, Diamond Irradiation changes diamond color by creating color centers, often followed by annealing. Disclosure is… Color Enhancement HPHT Color Treatment High pressure high temperature treatment can remove brown color or create fancy colors in…
Inclusions

Inclusions & features

Crystals Crystal Inclusions Under 10x loupe: solid, well-formed mineral crystals trapped inside the host gem. They may… Fractures Feathers and Fractures Under 10x loupe: irregular internal surfaces that catch light and appear bright, wing-like, or…
Identification

Instruments used

10x Loupe Your most-used instrument, start every examination here Thermal Probe Confirms diamond, but always follow up with a moissanite tester UV Lamp, Long Wave and Short Wave Fluorescence exposes treatments, synthetics, and origin Hydrostatic Scale Measures specific gravity, works even on opaque stones