Hello again friends of Steemit, today I decided to share with you something that I love a lot. I have always had some attraction for precious stones, I think they are a beautiful work that nature has and I would like to show you my little collection of them.

Precious stones, also called gems, are solid and hard mineral substances, used as decoration. Most of them are composed mainly of silicon, with the exception of diamond, consisting only of carbon. The value of these stones depends on their scarcity in nature and certain properties, such as their inalterability, hardness and beauty. The latter varies with the optical qualities of the stones, such as refraction, the play and intensity of the colors, the dichroism (two colors appear depending on their position with respect to light), transparency, brightness, etc. Between the gems they stand out, besides the diamond (formed by crystallization of the carbon), the emerald (green variety of the beryl), the amethyst (violet variety of the quartz), the opal (oxide of silicon hydrated), the topaz (silicate with fluoride of aluminum), sapphire (blue variety of corundum) and ruby ​​(red variety of corundum). The precious stones are worked and polished by specialized craftsmen called lapidarios.

These stones are molded into silicon carbide discs or natural sandstone lathes. The first step is to choose the desired shape (rounded, faceted), then fine polishing is done on cloth or wood discs with special powders.

Gems are usually identified through the analysis of their optical properties. The specialists in these studies are the gemologists, who use special instruments such as the refractometer (which measures the refractive index) and the polariscope (which determines if the light that crosses the crystal is polarized or not).

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