Diamond is a rare, naturally occurring mineral composed of carbon. Each carbon atom in a diamond is surrounded by four other carbon atoms and connected to them by strong covalent bonds – the strongest type of chemical bond. This simple, uniform, tightly-bonded arrangement yields one of the most durable and versatile substances known.
Diamond is the hardest known natural substance. It is also chemically resistant and has the highest thermal conductivity of any natural material. These properties make it suitable for use as a cutting tool and for other uses where durability is required. Diamond also has special optical properties such as a high index of refraction, high dispersion, and adamantine luster. These properties help make diamond the world’s most popular gemstone and enable it to be used in specialty lenses where durability and performance are required.
Because diamond is composed of the element carbon, many people believe that it must have formed from coal, but it is not true! Most of the diamonds that have been discovered were delivered to Earth’s surface by deep-source volcanic eruptions. These eruptions begin in the mantle, and on their way up they tear out pieces of mantle rock and deliver them to Earth’s surface without melting. These blocks from the mantle are known as xenoliths. They contain diamonds that were formed at the high temperature and pressure conditions of the mantle.
Diamond Gemstone Quality
The quality of a diamond that has been faceted into a gem is primarily determined by four factors: color, cut, clarity, and carat weight.
Color: Most gem-quality diamonds range from colorless to slightly yellow, brown, or gray. The most highly regarded and valuable diamonds are those that are completely colorless. These are the ones sold for the highest prices. However, another category of diamond gemstone is increasing in popularity. These are colored diamonds, which occur in a variety of hues including red, pink, yellow, orange, purple, blue, green and brown.
The value of colored diamonds is based upon the intensity, purity and quality of their color. Those with a saturated, vivid color are called “fancy-color diamonds” or “fancies”. On average, only one diamond in 10,000 has a color that earns the “fancy” designation. This rarity makes fancy-color diamonds extremely valuable. Some of them have sold at auction for over one million dollars per carat. They are some of the world’s most valuable and spectacular diamonds.
Clarity: The ideal diamond is free from fractures and inclusions (particles of foreign material within the gem). These detract from the appearance of the gem and interfere with the passage of light. When present in large numbers, dark colors, obvious positions or sizes then will significantly degrade the appearance of a cut gem and lower its value. They can also reduce the strength of the stone.
Cut: The quality of design and craftsmanship used in cutting a diamond is what determines its appearance. The angles to which the facets are cut, the proportions of the design, and the quality of the polishing are what determine its face-up appearance, brilliance, scintillation, pattern, and fire. Ideal stones are perfectly polished to be highly reflective and emit a maximum amount of fire. Corresponding faceted faces are equal in size and identical in shape. And, the edges of each faceted face meet perfectly with each of its neighbors.
Carat: Diamonds are sold by the carat (a unit of weight equal to 1/5th of a gram or 1/142nd of an ounce). Small diamonds usually cost less per carat than larger stones of equal quality. This is because very small stones are very common and large stones are exceptionally rare.
In B.C., reports of microscopic crystals from chromite are found on Olivine Mt. near Tulameen and also from Scottie Cr. and Bonaparte River near Ashcroft.
