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Shopping with Confidence
Integrity Pledge
“Natural Diamond Quality Assurance” Mark (NDQA)
Why Buy Diamond in Hong Kong and From DFHK Members
Shopping for Jewellery in Hong Kong - Tips and Advice
What is Diamond
How to Choose Diamond - 5C
Tips on Caring for Diamond
Diamond Grading
For Enquiry
   
 
What is Diamond

A diamond is a NATURAL mineral composed essentially of carbon crystallized at extremely high temperatures and pressures; in nature, diamonds form 150 to 200 kilometers or more below the earth's surface (see photo 1 & 2). Diamond is the hardest of all known natural substances (10 on the Mohs scale); its refractive index is 2.417, dispersion 0.044, specific gravity 3.52, and its luster is adamantine.

Photo 1   Photo 2
 
 

Diamond forms in the cubic, or isometric, crystal system (see photo 3), has four directions of perfect octahedral cleavage, and shows a step-like fracture surface. Its color ranges from colorless to yellow, brown, gray, orange, green, blue, white, black, purple, pink, and, extremely rarely, red (see photo 4).

Photo 3   Photo 4
 
 

Transparent and near-colorless in a desirable color (see photo 5), diamond is a highly valued gemstone; poorly colored or heavily included single crystals are used for a wide variety of industrial purposes; polycrystalline material is crushed and used as an abrasive powder.

 
Photo 5