Tags: Colour

Methods of Diamond Color Treatments

Methods of Diamond Color Treatments

Helen George 16/05/2020 0
Currently, there are two principal methods of permanently changing the color of a diamond: ♦ Irradiation + Heating ♦ High Pressure High Temperature Heat Treatment (HPHT treatment) Both of these treatment processes are considered legitimate as long as they're disclosed to buyers. Unfortunately, some people try to pass off treated diamonds as naturally colored in order to get a higher price. So before investing a high sum of money in a fancy-color diamond, have the stone tested by a reputable gem ...
Read More
Story of Fancy Colour Diamonds

Story of Fancy Colour Diamonds

Kenneth Lane 06/05/2020 0
On April 28, 1987, a 0.95 carat diamond was sold for $880,000 at Christie's in New York. It contained two large flaws, one of which was a deep cavity in the table (top center facet) of the diamond. Despite its flaws and small size, it set a new world record per carat price for any gem sold at auction: $926,000 (reported by the summer 1987 issue of Gems and Gemology). Why did that diamond command such a high price? Because its natural color was an extremely rare, deep, purplish-red. Color plays a...
Read More
How Objective are Diamond Colour Grades?

How Objective are Diamond Colour Grades?

Kenneth Lane 01/05/2020 0
Color grades are not as objective as people would like them to be. Even when the grader is someone as highly respected as the GIA, the color grade can be questioned. Russell Shor, senior editor of the JCK (Jewelers' Circular Keystone magazine), pointed out in their September 1987 issue that sometimes the grades of diamonds change when they are sent back to the GIA for re-examination. In 1995, Shor did a study of five diamonds which JCK sent to three major US gem labs. Only one of the diamonds re...
Read More
How to Grade Diamond Colour ?

How to Grade Diamond Colour ?

Kenneth Lane 01/05/2020 0
Probably the best way to learn to color grade is to ask your jeweler to show you how. He or she will have some loose diamonds, a paper or plastic white grading tray, possibly a set of graded comparison diamonds called master stones and a good diffused (not bare) light source such as a daylight-equivalent fluorescent light. You might be surprised when the jeweler places the diamond upside down on the tray and has you look at the color through the pavilion (the backside of the diamond). This, howe...
Read More
An Introduction to Diamond Colour

An Introduction to Diamond Colour

Claire Falkenstein 01/05/2020 0
When you look at diamonds in jewelry stores, they may all seem colorless. But if you look closely, you'll notice that they normally have slight tints of yellow, gray or brown. The strength of these tints partially determines the price of the diamond. Normally the less color a diamond has the more it costs. However, prices start rising when the color reaches a point just stronger than light yellow (a grade designated as fancy yellow). As the intensity of fancy-yellow diamonds increases so does th...
Read More