diamond treatments

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Sometimes diamonds are enhanced to improve their appearance.  Although these enhancements may improve their quality, these treated diamonds are worth considerably less than untreated diamonds of like quality.

Below is a list of diamond treatments, along with descriptions and photos.

coating

Diamonds can be coated to give them a fancy-colored appearance

A somewhat-durable, colored film is applied to the surface of a diamond, giving it the appearance of being fancy-colored.

fracture filling

Rainbow flash inside a fracture-filled diamond

Large cavities and/or fractures in a diamond are filled with a clear acrylic material.  Look for the "rainbow flash effect" extending into the diamond from surface-reaching fractures.​​

Red flash in this fracture-filled diamond

The foreign material in this fracture-filled diamond has an unusual appearance

hpht

High pressure, high temperature treatment process that can sometimes produce colorless or near-colorless diamonds.  HPHT treatments are usually only detectible through advanced laboratory testing.

laser drilling

Tiny drill holes are visible when reflecting light off the table of this clarity enhanced diamond

Large, unattractive, black carbon inclusions can be removed by using a microscopic laser to drill into the diamond and burn the inclusion.  It is then either bleached or filled with a clear acrylic material to make it less visible.  Look for tiny tube-like channels that reach the surface of the diamond.

Profile view of a shallow drill hole in this clarity enhanced diamond

All photos courtesy of Scott Papper, GG, ASA, CMA, RGA, AJP, CMSP, CSSP