Some fascinating little-known diamond characteristics
By Margi Jenks
About once a month a visitor will ask a question about diamonds that I can’t answer. So, after a little research I will share some of my more interesting findings. We all know that diamonds are amazingly hard, but did you know that they are also one of the best conductors of heat? They conduct heat so rapidly that they can be heated red hot, then plunged into freezing liquid nitrogen, and they will not shatter like most materials. This characteristic is the reason that diamonds will feel cool to the touch. If you heat diamonds enough their outsides will oxidize to black, but in air that temperature is 700 degrees centigrade; in high-purity argon gas the oxidation temperature reaches 1700 degrees centigrade. Because of this thermal characteristic, diamonds are sometimes used as heat sinks in electronic equipment.
Next, diamonds are poor conductors of electricity. In fact, instead they are very good resistors/insulators. This characteristic is unusual because most elements that readily conduct heat are also good conductors of electricity. Also, diamonds are the least compressible of all known materials.
Finally, our visitors ask whether or not diamonds will fluoresce under ultra-violet or “black” light. Between twenty and thirty percent of all diamonds will fluoresce, but generally fairly weakly. The most common fluorescent color is a very subtle to strong blue. This color creates problems in grading the diamonds. The whiter the diamond is the higher its value. If a yellow diamond fluoresces, the blue fluorescent color will cancel out the yellow color and the diamond will be a “false white”. The origin of the fluorescence is not clear, but can be made stronger by cold. The fluorescence also depends on whether the ultra-violet light is long-wave or short-wave. Natural diamonds do not fluoresce at all under short-wave ultra-violet light, but synthetic diamonds will fluoresce strongly. Waymon has tested our Crater diamonds and only one or two out of thirty diamonds fluoresced. We have diamond search rules against using electric or battery operated equipment to search for diamonds. However, we aren’t open at night when the fluorescence would be brightest, and the fluorescence of our diamonds is too slight to show during the day. Thus, even if we did allow our visitors to use ultra-violet lights, they still would not be useful tools for finding Crater diamonds.
Search area last plowed: October 21, 2009, Total diamonds so far in 2010 - 11
Diamonds registered January 11th to January 24th (100 pts. = 1 carat):
January 12 - David Anderson, Kent City, MI, 22 pt. white
January 16 - Billy Moore, Murfreesboro, AR, 65 pt. yellow; Tim Pittman, Jacksonville, AR, 16 pt. white
January 20 - Beth Gilbertson, Ponca Springs, CO, 53 pt. white
January 21 - Nancy Reed, Aberdeen, WA, 26 pt. yellow
January 22 - Luther Hart, Cotton Valley, LA, 8 pt. white; Pat Choate, Jacksonville, AR, 18 pt. brown
January 24 - Kenny & Melissa Oliver, Rosston, AR, 3 pt. white, 17 pt. white