natural material that looks like diamond.

manmade material made primarily of carbon forming in a different crystal system than natural diamond.

manmade material that looks like diamond.

manmade material with essentially the same physical, chemical, and optical properties as natural diamond.

is limited to fancy-colored melee, which is mostly synthetic.

makes up a substantial portion of the market.

is currently impossible because the synthetics are too highly included.

is limited by high production costs.

yellow or brown.

colorless.

blue

pink

Xenocryst

Metallic flux

Garnet crystal

Diopside crystal

Strong blue under both longwave and shortwave.

Yellow to greenish yellow under both longwave and shortwave.

Strong yellow under longwave and none under shortwave.

Blue under longwave and weak yellow under shortwave.

High-energy electrons in a linear accelerator

X-rays

Ultraviolet radiation

Radium compound

don't grade fracture-filled diamonds.

only treat diamonds with eye-visible feathers.

grade diamonds before they fracture fill them.

give fracture-filled diamonds grades that are one grade lower than they appear to be.

D grade colorless

intense blue

esmerald green

brown , orange and yellow

ammonia in cleaning solutions.

chlorine in swimming pools.

heat during routine repairs.

ultraviolet rays in sunlight.

can be easily determined with standard gemological equipment.

should usually be determined by a gemological laboratory.

can be determined using a DiamondSure.

cannot be determined for most diamonds.

1990

1940

1950

1800

Flash effect

Color zoning parallel to facet junctions

Hourglass graining

Etched or frosted naturals

usually reduce the clarity grade.

become permanent clarity characteristics.

aren't permanent, so major labs won't grade them.

don't need to be disclosed to customers.

distinctive color zoning.

only shallow penetration of the color.

usually green or dark green colors.

blue or blue-green colors.

is fracture-filled.

is irradiated.

is coated.

has undergone HPHT treatment.