Являются ли драгоценные камни драгоценными камнями?
A mineral is a naturally occurring chemical compound, usually of crystalline form and not produced by life processes. It has one specific chemical composition, whereas a rock can be an aggregate of different minerals. The science is mineralogy.
Most gemstones are minerals
They have various physical properties. Their description depsnds on their chemical structure and composition. Common distinguishing characteristics include crystal structure and habit, also hardness, lustre, diaphaneity, colour, streak, tenacity, cleavage, fracture, parting, specific gravity, magnetism, taste or smell, radioactivity, and reaction to acid.
Exemple of mineral : Quartz, diamond, corrundum, beryl, …
It is important to distinguish between synthetic stones, and imitation or simulated gems.
Synthetic gems are physically, optically and chemically identical to the natural stone, but made in a Factory. In the trade maket, Stones dealers use often the name “lab created”. It makes the synthetic stone more marketable than “factory created”.
Exemple of Synthetic stones : Synthetic corrundum, synthetic diamond, synthetic quartz, …
Examples of Artificial stones include cubic zirconia, composed of zirconium oxide and simulated moissanite, which are both stones simulants. Imitations copy the look and color of the real stone but possess neither their chemical nor physical characteristics.
Moissanite actually has a higher refractive index than diamond and when presented beside an equivalently sized and cut diamond will have more “fire” than the diamond.
Rock is a natural substance, a solid aggregate of one or more minerals or mineraloids. For example, Lapis lazuli is a deep blue metamorphic rock. Its classification is semi-precious stone. The most important component of lapis lazuli is lazurite (XNUMX% to XNUMX%), a feldspathoid silicate.
A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorphous glass and not a crystal.
Jet is derived from decaying wood under extreme pressure. Opal is another one because of its non-crystalline nature.
Man‐made glass, plastic, …