Selling Diamonds

(via Diamond Promotion Service) The Beauty Of A Diamond: 36. The beauty of a diamond comes from the light that passes through it or is reflected from it. Light is something that we take for granted, without recognizing that it is made up of countless rays shooting in all directions. To understand how light makes the beauty of a diamond, we have to think of it in terms of individual rays.

When a ray of light strikes a diamond, 18 percent is reflected allowing 82 percent to enter the stone. As a ray of light enters the diamond, it changes direction according to the refractive index and then keeps going until it strikes the inside of another facet. If it strikes that facet within the critical angle (24.1º), it goes on through and leaves the diamond. Otherwise, it bounces off in a new direction, still within the stone.

The proportioning of the diamond and the cutting of the facets to precise angles are designed so that as much light as possible can go into the stone from the top, bounce around inside, and then come back out the top again with brilliance, fire and scintillation. A diamond whose proportions are too deep will leak light through the facets below the girdle. One whose proportions are too shallow will also leak light, and it may have a fish eye dead spot on top.

The larger the diamond, of course, the larger the top surface area that can admit light. However, small diamonds are just as efficient in their handling of light and produce just as beautiful an effect.

37. Brilliance. Brilliance, fire and scintillation are often confused. In the strictest sense, brilliance is the intensity of the reflections of white light from the diamond that meet the eye when we look down into it. These are the internal reflections of light from the inside surfaces of the facets below the girdle. Because it is so hard, the diamond takes a high polish and so gives off more brilliance surface reflections than does any other gem. So the diamond’s brilliance comes from its internal and external reflections of light.

38. Fire. The diamond’s ability to break up a ray of white light into all colors of the spectrum gives it fire. The dispersion is greater than any other precious gem. The width of this dispersion, the amount of fire, is least when a ray of light leaves the diamond at an angle (24.1°) near the perpendicular. So the 32 facets between the girdle and the table are placed to take maximum advantage of the diamond’s power of dispersion, to give the diamond the most fire possible.

39. Scintillation. The nursery rhyme sings, ‘Twinkle, twinkle, little star…like a diamond in the sky.’ Scintillation is that twinkling or flashing of light from the facets of a diamond as it moves. This depends primarily on three things: the sizes of the pavilion facets below the girdle; the number of facets visible to the eye as the diamond moves; and the high polish or luster of the facets reflecting the light. Scintillation explains why diamonds are so much more beautiful when they are in motion while being worn than they are at rest. Moving either the eye or the light source will also cause scintillation.

Selling Diamonds (continued)