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How to Tell If a Diamond Is in a Rock

Diamonds occur naturally in the environment, and are most often found in placer deposits and kimberlite pipes near volcanoes. Diamonds, composed of carbon that has been subjected to intense heat and pressure, are the hardest substance on earth. Diamonds make excellent jewelry pieces because of their desirable qualities, including luster, hardness, translucence and color. Spotting a diamond in a rock can be tricky; an observer must know exactly what to look for to identify a true diamond in the rough.

Things You'll Need

Magnifying glass
Ice pick
Cotton swabs
Alcohol
Tweezers
Newspaper
Ultraviolet light

Instructions

- 1
  Study the features of the sample, using a magnifying glass. Most true diamonds are multisided, with as many as eight or 12 sides. The sides, or faces, will be flat with angular planes opposing each other. A diamond might also have a cube shape with four sides. Diamonds that have considerable wear as a result of water weathering will appear as rough, oblong shapes with rounded edges, ribs or other deformities.
- 2
  Liberate the sample from the rock sample, if possible. You will need to see a large portion of it to determine its authenticity. Use an ice pick, or any small tool with a sharp head, and scratch around the perimeter of the sample's surface. Undercut it enough so you can remove it from the rock. Avoid contacting the sample with the tool's surface as much as possible.
- 3
  Wipe the sample clean with cotton swabs and alcohol. Hold the sample up to your mouth with a pair of tweezers. Use your breath to fog it, as you would a pane of glass or a mirror. If the surface of the sample remains fogged for 2 to 4 seconds, it fails the diamond test. A real diamond will instantly disperse the heat from your breath and the fog will disappear before you have a chance to look at it.
- 4
  Hold the sample over a small piece of newsprint with tweezers. Hold a magnifying glass over the sample and see if you can pick up any legible print underneath the sample. If you can read anything at all, it indicates another type of gem and not a diamond. A diamond will have a frosty glaze.
- 5
  Place the sample on a flat surface, or facing upward if it is still entombed in a rock. Hold an ultraviolet light over the sample and watch to see if it fluoresces blue. A medium or strong blue color will identify a diamond, but it will be of a lesser quality (industrial grade) than one that has more purity. In rare cases, a diamond of exceptional quality will not fluoresce blue, so keep this in mind.
- 6
  Take the rock to a jewelry store or outlet that has an appraiser or gemologist on staff. You might have to pay a small fee and leave the sample for a day or so, or you might get lucky and be rewarded with an instant courtesy evaluation at no cost. The appraiser will examine the sample and the base rock that holds it.

Rock Collecting