Precious and semiprecious stones refer to minerals, which are different from others due to their special characteristics, such as some organic materials that have beauty and stability and are used in decorations. Most of the gems are crystalline minerals except pearl, coral, amber and etc.
The most important factor in precious stones is their color. Often color belongs to stones and it seems transparent and semitransparent. In specific cases, color is related to light phenomena in stones, as play of light in Opal, adularescence in moonstone, color of Labradorite surface or light absorption phenomenon in star-shaped ruby and sapphire and cat eye sapphire.
For using a stone or gem as jewel, certain hardness is required. To determine the value and price, scarcity is considered other than beauty.
The Properties that place mineral and nonmineral among precious stones are:
1. Beauty, shine and luster
Physical Properties of Precious Stones
Physical characteristics of gems:
· Specific weight
· Breaking way and Cleavage
Properties of Precious Stones
Value and price of precious stones are due to some properties such as color, hardness, beauty, and luster. Scarcity and demand & supply are also effective.
Precious and semiprecious stones are either simple and without color or have very beautiful colors. If they are not flat, crystalline and lustrous, they will have beautiful colors like turquoise and sapphire.
Artificial Gem or Jewel
Artificial stones or gems is referred to artificial and laboratory production of precious ores through scientific methods. Production of artificial gems and jewels began about 50 years ago. It is expected that artificial gems and jewels have the same physical and chemical properties of natural gems; but in nature they are different from each other. So artificial gems may have some differences in structure and other properties with their natural minerals.