| Diamonds almost always have defects and one | | | | rock drill bits. South African mines contain |
| of the main defects is carbon spots. Their | | | | some specks of black opaque carbon which can |
| influence upon diamond value has to be taken | | | | constitute very undesirable defects in |
| into account along with the influence of | | | | stones. |
| color. A stone may have great color, yet may | | | | |
| yield some carbon imperfections making it far | | | | Often times a large stone can have a large |
| less valuable than an off color stone. | | | | defect in it, and it will have to be cut into |
| | | | several different smaller pieces. Diamond |
| A truly colorless diamond is very rare, so it | | | | cutters are often times after less sizable |
| may be stated that one perfect in | | | | stones to eliminate carbon spots. One of the |
| crystallization is also seldom. A perfect | | | | more serious effects that a carbon spot may |
| crystal is rarely found in nature. The | | | | have on a diamond is it lying in a more |
| diamond cutter tries to remove as many of | | | | conspicuous spot, the light may hit this spot |
| these imperfections as possible, without | | | | and reflect the carbon spot. This may make |
| cutting the weight of the actual stone. | | | | the stone appear to have many carbon spots |
| Usually after the stones are cut most of them | | | | instead of one. The cutter wants to cut the |
| still have some imperfections and blemishes. | | | | diamond in a way that puts the carbon spot in |
| | | | a less conspicuous place. Often times if the |
| One of the most common types of imperfection | | | | stone is going to be placed in a setting they |
| is known in the trade as carbon or as carbon | | | | will bout the carbon spot on a side of the |
| spots. Diamonds are one of the many types of | | | | fitting, thus covering the fitting. |
| carbon. Graphite is a second variety, and | | | | |
| amorphous carbon such as charcoal, lampblack | | | | When a carbon spot can be seen by the unaided |
| is a third. | | | | eye, it is a very bad defect, and greatly |
| | | | affects the value of the stone. If a defect |
| There is no hard line between the various | | | | is very slight it may not affect the value of |
| forms of carbon. Artificial attempts to make | | | | the stone too drastically. Many of the |
| diamonds have yielded both genuine diamond | | | | whitest diamonds seem to be afflicted with |
| and also very hard, black, opaque carbon in | | | | carbons. |
| the same lot, and even in the same crystal, | | | | |
| and apparently in the natural formation of | | | | Many of the fine blue-white stones are |
| diamonds some of the material is frequently | | | | affected by carbons, while diamonds of the |
| left in a black and opaque, but very hard, | | | | poorer colors are less likely to have |
| condition. Masses of black carbon are | | | | carbons. A defect that may resemble a patch |
| sometimes found in Brazil, they are sold | | | | of carbon may result in cracks of the |
| under the name of carbonado. People often | | | | diamond. Diamond dust and oil can slip into |
| use the black carbon to be used in mechanical | | | | a crack and create a defect. This problem |
| purposes due to its toughness and great | | | | may be avoided by using a nearly dry |
| hardness. This black carbon is often used for | | | | polishing wheel while working around cracks. |