Precious stones differ from semi-precious and semi-precious stones in many ways. But this division is also conditional. The most expensive, rare and durable gemstone is diamond.
Signs by which stones are classified
There are several classifications of gemstones, based on such characteristics as the hardness or light scattering of the stone, the composition of the mineral, crystallographic features, and the prevalence in nature. That is why the division into precious and semi-precious stones is very arbitrary.
For the first time, the division into types of precious stones was proposed by M. Bauer in 1896. Later, many scientists, including A. E. Fersman and V. I. Sobolevsky, turned to the improvement of this issue.
It is customary to divide jewelry stones into three types: precious, semi-precious and semi-precious.
Gems
Precious stones are minerals that are distinguished by their special brilliance, beauty and play of color, or strength and hardness, and which are used as jewelry.
According to a simplified classification, the first grade gemstones are: diamond, sapphire, chrysoberyl, ruby, emerald, alexandrite, spinel, lal, euclase.
The second grade of precious stones is: topaz, beryl, aquamarine, red tourmaline, phenakite, demantoid, blood amethyst, hyacinth, opal, almandine, zircon.
Diamond and brilliant are one stone, which is a type of crystalline carbon. The first name denotes a stone in its natural form, and the second - with a cut.
There are no such terms as semi-precious and ornamental stones, since they differ from precious stones only in their wider prevalence and less pronounced properties, which is reflected in the price of products with them.
Among the semi-precious stones are: garnet, epidote, turquoise, dioptase, green and variegated tourmalines, rauchtopaz, rock crystal, chalcedony, light amethyst, sun and moonstone, labrador.
Ornamental (semi-precious) stones include: jade, bloodstone, lapis lazuli, amazonite, labrador of lower quality, varieties of spar and jasper, smoky and rose quartz, vesuvman, jet, corals, amber, mother-of-pearl.
Modern classification of gemstones
Professional jewelers and mineralogists consider the best and most modern classification proposed by Professor E. Ya. Kievlenko.
The first group includes jewelry (other synonymous names are cut, precious) stones:
- diamond, blue sapphire, emerald, ruby, constituting the first class;
- alexandrite, orange, yellow, violet and green sapphire, noble jadeite, noble black opal, which are included in the second class;
- demantoid, noble spinel, aquamarine, topaz, rhodolite, noble white and fire opal, red tourmaline, moonstone (adularia), which represent the third class;
- blue, green, pink and polychrome tourmaline, turquoise, chrysolite, noble spodumene (kunzite, hiddenite), zircon, yellow, green, golden and pink beryl, pyrope, almandine, amethyst, citrine, chrysolite, chrysoprase, which the scientist attributed to the fourth class.
The second group classifies ornamental, or stone-cut, stones:
- rauchtopaz, amber-succinite, hematite-bloodstone, jadeite, rock crystal, lapis lazuli, malachite, jade, aventurine, belonging to the first class;
- agate, cacholong, colored chalcedony, amazonite, heliotrope, rhodonite, rose quartz, iridescent obsidian, labradorite, ordinary opal, belomorite and other opaque iridescent spars, which make up the second class.
The third group is represented by decorative facing stones, among which: jasper, written granite, marble onyx, petrified wood, listvenite, jet, jaspilite, obsidian, selenite, aventurine quartzite, fluorite, agalmatolite, colored marble, patterned flint.
