Jewelry stones are currently commonly referred to as all materials used for the production of jewelry. But when studying jewelry materials, it is necessary to single out the concept of "gemstone" separately.
Precious stones are natural minerals formed in a complex way in the earth's crust. The main requirement for a stone to be considered unique is its rare occurrence. It is also necessary that the mineral be sufficiently hard to resist external influences (not scratched, not chipped).
By the Federal Law "On Precious Metals and Precious Stones, " Precious stones include natural diamonds, emeralds, rubies, sapphires, alexandrites, and natural pearls.
One of the essential features of colored gemstones as a commodity is their high cost.
"Genuine" and "natural" are synonymous and refer exclusively to natural substances formed without human intervention.
As a result of the development of the mining industry and new technologies, the range of gemstones used in jewelry has expanded. In addition, designers are increasingly offering to use the latest or unconventional materials - artificial stones and imitations - in jewelry production.
Many jewelry stones are characterized by the same or similar signs, making it difficult to diagnose them. For example, among transparent and opaque stones, groups of the same color can be distinguished - green, pink, red, blue, etc. Methods of their diagnosis are based on determining the most important physical properties and internal features of minerals.
The definition of jewelry stones is a highly complex matter. It requires not only knowledge of mineralogy but also a lot of experience, attention and is, to some extent, an art. There are well-known experts who, it would seem, by some famous signs, determine jewelry stones - by the feeling of heat or cold emanating from them, by the shape of a drop of liquid on their surface, the presence of "sparks", shades of color. These signs are based on specific physical properties of stones: thermal conductivity, wettability, refractive indices. Specialists in the field of determining (diagnosing) stones are called gemologists.
Currently, the diagnosis and definition of gemstones is carried out with the help of special devices.
A preliminary conclusion about the gemstone name is given based on the results of its visual diagnostics - by determining the color, transparency, gloss.
Transparency is understood as the ability of a solid body to pass rays of light through itself to one degree or another. Clarity of the gemstones depends on the crystal structure, the presence of cracks in them, concrete and gas-liquid inclusions.
The transparency of jewelry stones is determined visually when viewing them in the light. According to the degree of openness, jewelry stones are divided into:
transparent - all colorless and slightly colored inserts, through the plates of which (thickness 3-5 mm) the object is visible (examples: topaz, chrysolite);
translucent or translucent - through which things are not visible (samples: jade, carnelian);opaque (samples: malachite, turquoise).
Along with transparency, one of the essential diagnostic signs of jewelry stones is luster. It is determined visually. The shine is created by the light reflected from the surface of the standing stone. By the nature of the luster, the following types are distinguished: glass (emerald, sapphire), fat (jade), diamond (diamond), metal (hematite).
For most jewelry stones, one of the most characteristic distinguishing features is coloring (color). In gemology, it is determined visually against the background of a sheet of white paper.
Stones are distinguished by color:
- colorless: diamond, rhinestone, leucosapfyre, moonstone, opal, topaz, spinel;
- red: almandine, obsidian, opal, pyrope, ruby, zircon, spinel;
- pink: kunzite, rhodolite, rose quartz, rubellite, topaz, spinel;
- orange: sapphire, carnelian, spessartin, topaz, amber;
- green: alexandrite, beryl, demantoid, jadeite, emerald, cat's eye, sapphire, uvarovite, chrysoberyl, chrysolite, chrysoprase, chromdiopside, zircon, spinel;
- yellow: heliodor, sapphire, topaz, chrysoberyl, chrysolite, cymophane, zircon, citrine, amber;
- brown: topaz, zircon, smoky quartz;
- blue: aquamarine, sapphire, tanzanite, topaz, zircon, spinel;
- blue: sapphire, spinel;
- purple: almandine, amethyst, kunzite, sapphire;
- gray: smoky quartz, obsidian, chalcedony.
For a more accurate diagnosis of a gemstone in special scientific laboratories, gemological devices are used to measure optical constants: refractive index, luminescence, pleochroism, and other properties.
One of the essential aspects of choosing the right jewelry is to buy the product at a fair market price. It is defined as the buyer's price to pay to the seller, provided that no one forces anyone and both have approximately equal knowledge in this area. Current market prices are considered when evaluating precious stones, which are published in unique international price lists. It should be taken into account that wholesale prices are several times lower than retail prices.
The factors used in assessing the quality and value of jewelry stones are:
- Color (the color of the stone in volume).
- Purity or clarity (the degree of absence of cracks and other internal defects).
- Cut quality.
- Weight in carats.
For the correct evaluation of a jeweler's stone, it is necessary to find out:
- what is the weight of the gemstone;
- how much does it cost per carat on the market;
- does the gemstone have a good cut;
- aren't there a lot of inclusions in it that negatively affect its beauty;
Whether the stone has been subjected to ennobling is an artificial change in color or purity.
Jewelry stones use in carats. The price per carat (200 mg) is the most common unit of comparison for colored stones. The mass of jewelry stones in carats with an accuracy of the second decimal place.
The price per insert (per piece) for cut stones uses commercial quality (very defective and often cut with a cabochon or table cut). In this case, when selling, the size and shape of the inserts are indicated.
The weight and size affect the pricing of the gemstone. Usually, the greater the mass of a gemstone, the higher the price per carat. But if the stone is enormous - more than 50 carats, it is more challenging to sell it because of the very high cost, unless it is a rare gemstone. It is also necessary to consider the fact that stones of the same mass have different sizes since their specific gravity is separate. Some precious stones are more often large (topaz). The group of more than 5 carats is infrequent for other precious stones, so they are valued more expensive (ruby).
If you love gems and jewelry. You believe in magic power. And you know which stone suits you according to the horoscope, then the pillow will decorate your interior. There are also a few things from the collection (accessories) "Precious stones." Purple amethysts, green peridots, and orange garnets are scattered artistically on the beautiful royal blue background.