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