DIAMOND. The mere mention of the word fills the mind with a multitude of concepts and images. Diamond is a mineral, a natural crystalline substance, the transparent form of pure carbon. Diamond is something superb, the peerless "king of gems" that glitters, dazzles, and symbolizes purity and strength. Diamond is for engagement and the 75th wedding anniversary, for a commitment to never-ending love. Diamond is indomitable, the hardest surface known. Diamond is exotic, formed in Earth's interior and shot to the surface by extraordinary volcanoes. A diamond is likely the oldest thing you will ever own, probably 3 billion years in age, fully two thirds the age of the Earth. Diamond is a strategic and high-tech supermaterial for our technological society. Diamond is a shape. This exhibition presents the fascinating story of the nature of diamonds.

16.2 Diamond Origin and Occurrence

Diamonds occur in two general types of deposits world wide:

• volcanic pipes, also known as kimberlite pipes

• alluvial, or placer, deposits, which were formed by the erosion of diamond pipes over millions of years.

16.2.1 Geological Significance of diamond origin, discovery and occurrence
16.2.2 Dynamic geological environment of diamond and its conditions of growth
16.2.3 Evidence for origins
16.2.4 Geographical Distribution and mine localities in terms of geological occurrence
16.2.5 Primary and Secondary occurrences
16.2.6 Exploration, Reserves and Ore

16.4 Properties of Diamond
16.4.1 Relevant descriptions of the gemological properties and their practical exploitation
16.4.2 Dispersion and Fire
16.4.3 Reflectivity and Lustre
16.4.4 Brilliance
16.4.5 Directional Optical Properties
16.4.5.1 Polarisation
16.4.5.2 Refraction and the measurement of RI
16.4.6 Non-optical properties
16.4.6.1 Durability
16.4.6.2 SG
16.4.6.3 Electrical properties
16.4.6.4 Thermal properties
16.4.6.5 Wettability
16.4.7 Non-optical directional properties
16.4.7.1 Grain
16.4.7.2 Cleavage
16.4.7.3 Differential hardness
16.4.7.4 Crystal form in relation to the crystal structure of the diamond
16.4.7.5 Their significance in identification and manufacture.

16.7 Mining and Recovery
16.7.1 Main methods of modern mining
16.7.2 Open-pit and underground mining
16.7.3 Brief history of mining methods
16.7.4 Diamond pipe and alluvial diamond mining
16.7.5 Marine mining
16.7.6 Stages of recovery
16.7.6.1 Treatment
16.7.6.2 Concentration
16.7.6.3 Separation

Diamonds come in all shapes and sizes. Among them, the best known are"

• Round Brilliant
• Princess Cut
  
• Emerald Cut
• Asscher Cut
• Radiant Cut
• Marquise
  
• Pear Shape
• Heart Shape
• Trilliant
• Cushion Cut

In this section, we will cover answers to common questions such as: