Diamond

Diamond is an extraordinary mineral with extreme hardness and inherent beauty that is sought for personal adornment and industrial use. Because the genesis of this unique mineral requires extreme temperature and pressure, natural diamond is so rare that some diamonds are one of the most valuable commodities on Earth, based on weight.

Type

Mineral

Mineral Classification

Native element

Chemical Formula

C

Streak

Colorless

Mohs Hardness

10

Crystal System

Isometric

Color

Typically yellow, brown or gray to colorless. Less often blue, green, black, translucent white, pink, violet, orange, purple and red.

Luster

Adamantine

Fracture

Conchoidal

Description

Diamond is an extraordinary mineral with extreme hardness and inherent beauty that is sought for personal adornment and industrial use. Because the genesis of this unique mineral requires extreme temperature and pressure, natural diamond is so rare that some diamonds are one of the most valuable commodities on Earth, based on weight.

Relation to Mining

Natural diamond has been discovered in 35 countries. Some diamonds have been found in the United States. Colorado, for instance, has produced a small number of diamonds.

The following countries produce industrial grade diamonds: Russia, Congo, Botswana, South Africa, and Zimbabwe.

Geologically speaking, natural diamonds are found in two environments. Most are found in kimberlites, which are pipe-like formations created as a result of volcanic and tectonic activity.

The second geological source for diamonds is placer deposits. The diamonds are easily weathered out of their kimberlite host rock and are washed away by streams and rivers. When these streams slow down, the diamonds are deposited in the stream sands in what are called placer deposits.
(Industrial Minerals and Rocks,  7th Edition. Kogel et al. SME, 2006.)

Open-pit diamond mines are typically designed to recover as little as 100,000 to more than 10 Mt of ore per year. Annual diamond production may range from several thousand carats to a few million carats. For example, the Finsch mine in South Africa, produced about 5 million carats annually between 1981 and 1991, whereas annual diamond production for the extremely rich Argyle lamproite reached a record 39 million carats during the height of operation.

Fewer than 30% of diamond mines are underground. The diamond ore must be of relatively high value, because the cost of underground mining is considerably higher and the amount of ore recovered is considerably lower. Some mines in South Africa reach depths of over 4 kilometers. Open pits may have mine lives of 2 to 50 years.  Synthetic diamond is used in the majority of industrial diamond consumption.  The process of creating synthetic diamonds allows the removal of impurities and produces a product with consistent physical properties.

Uses

Because it is the hardest substance known to be naturally formed on Earth, diamond will cut through any material. Consequently, it is used as an abrasive and in cutting and grinding applications. Industrial diamonds are embedded in large steel drill bits to drill into rock for wells to find water, oil, and natural gas. It is also important in the manufacture of machinery for drilling and cutting metal machine parts.

Natural diamond is now used for less than 1% of all industrial diamond used, synthetic diamond is the primary product used in industry.