In this 3rd part of our series on interesting and unique facts and features of diamonds, we look at numbers 39 - 51.
39. A diamond is per weight the most precious thing in the world, but is made from the most common material that is known
40. In 1980, William Goldberg paid US$1 million for a 0,96ct red diamond, still the world‚s most expensive material per weight
41. In the absence of oxygen a diamond will melt at 6,900 Celcius - 2.5 times the melting point of steel
42. In the presence of oxygen a diamond will burn with a blue flame at 950Р’С”Celcius and change into a gas called carbon dioxide
43. If a house burns down all that may be left of diamond jewellery is a molten lump of metal
44. HOwever, if the temperature during a house burn is not high enough, diamonds may survive, but they will be covered with a soft white skin, which can be polished away
45. Diamonds are cold to the touch because they are very good conductors of heat ‚ four times better than copper
46. Diamond testing machines, aka thermal conductivity meters, use the high heat conductivity of diamond to separate it from cubic zirconia and other colourless gemstones
47. Diamonds are very poor conductors of electricity, due to the fact that in a diamond's structure there are no free electrons. All free electrons of the carbon atoms are used to hold the atoms together, thus its exceptional hardness
48. The atmosphere of Venus was first analyzed through a diamond window of a US spacecraft - only diamond had the transparency and strength to cope!
49. A diamond will glow or fluoresce in blue, green and yellow colours when exposed to ultraviolet light
50. Diamonds also shows phosphorescence, i.e. they continue to glow very faintly, after the removal of the ultra violet light source
51. The phosphorescence of man made diamonds is different to that of natural diamonds. This difference is used to distinguish natural diamonds from those made in the laboratory
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