Phenomenal Stones
Phenomena are the gemstone equivalents of "special effects". They signify extremely special properties in stones, and because of this, these stone command special prices! There are many kinds of phenomenal gems, and we hope this article will make these terms clear.
First of all, let us consider asterism. This phenomenon exhibits itself in certain types of corundum (sapphire and ruby), garnet, spinel, diopside, beryl, quartz, and orthoclase. It comes from the Latin word for star. When this phenomenon is present, a four-, six-, or, rarely, twelve-rayed star is displayed on the surface of the stone. This is usually caused by needle-like inclusions within the stone, which are aligned in four, six, or twelve ways, and cause the light to reflect in a star-shaped pattern. A stone especially valuable if the center of the star hovers right over the center of the stone! A stone must be a cabochon (dome-topped stone) in order to display this.
First of all, let us consider asterism. This phenomenon exhibits itself in certain types of corundum (sapphire and ruby), garnet, spinel, diopside, beryl, quartz, and orthoclase. It comes from the Latin word for star. When this phenomenon is present, a four-, six-, or, rarely, twelve-rayed star is displayed on the surface of the stone. This is usually caused by needle-like inclusions within the stone, which are aligned in four, six, or twelve ways, and cause the light to reflect in a star-shaped pattern. A stone especially valuable if the center of the star hovers right over the center of the stone! A stone must be a cabochon (dome-topped stone) in order to display this.