There are many kinds of synthetic gems on the market. In the process of buying synthetic gems, people can choose a suitable gem according to their own preferences. Although synthetic gems can't be compared with natural gems, they are basically the same in composition and structure. Let's take a look at the basic knowledge of synthetic gems with edge shaw. What is a synthetic gem?

Synthetic gems are crystals, amorphous or polymers made entirely or partially by human beings, and have known counterparts in nature. Its physical properties, chemical composition and crystal structure are basically the same as the corresponding natural jewelry and jade. Synthetic gemstones have a history of nearly 200 years. 18 19, Dr. E.D. Clark put two rubies on charcoal with a newly invented blowpipe, melted them into a small ball, and accidentally got a new product-ruby glass.

Synthetic method of synthetic gem

The synthesis methods of single crystals can be divided into three categories:

1. Crystallization from the melt: use chemical reagents with the same chemical composition as the crystal, mix and melt them in the correct proportion, and then cool and crystallize under controlled conditions to grow gems.

2. Crystallization from the melt: the corresponding chemical components are dissolved in the liquid, and the gem is crystallized and grown on the subgrain under controlled conditions.

3. High-temperature and high-pressure crystallization (such as diamond): In the high-temperature and high-pressure reaction chamber, carbon dissolves in the high-temperature zone, crystallizes in the low-temperature zone, and grows crystals.

Types of synthetic gemstones

Artificial rutile, artificial cubic zircon, artificial sapphire, artificial spinel, artificial rutile, artificial metamorphic stone, artificial diamond, artificial emerald, artificial opal, artificial chronometer, etc.

The difference between synthetic gemstones and natural gemstones

Synthetic gemstones and natural gemstones are almost the same if only their appearance or physical properties. They can have nearly or exactly the same specific gravity, the same hardness, and some even have overlapping fluorescence reaction and absorption spectra, which is really difficult to distinguish. If only from the aesthetic point of view, then many synthetic gems are more beautiful than ordinary natural gems. In fact, the difference between the two is only the process of formation. Shicheng Gem and artificial gem are both produced by artificial techniques such as high temperature, high pressure and chemical reaction. Simulate some natural conditions in a laboratory or factory. The growth time of synthetic gems may be weeks or months. Generally speaking, it has a short growth cycle and can be grown in batches in a short time. Natural gems are formed during the formation and change of natural rocks because of certain conditions (such as chemical composition, temperature, pressure, etc. ) is especially suitable for the growth of some crystals.

The changes in nature are very long, ranging from tens of thousands of years to millions or even hundreds of millions of years. And the changes in this process are very complicated. The original gem crystal may be completely or partially destroyed by geological processes such as earthquakes, or it may react with later chemical solutions to form new minerals (not necessarily gems), so there are very few minerals that have survived to this day and can be found as gems.

To find and explore these gems on the earth, besides luck (accidental opportunity), it takes a lot of labor and effort. This difference in formation process and quantity is actually the difference in value between natural gemstones and synthetic artificial gem. Natural gems are even rarer and more precious, because people think that owning them is a symbol of wealth and are willing to buy them at a higher price.

Identification method of synthetic gemstones

Take ruby recognition as an example.

1, from the appearance, most of the finished products are perfect, colorful and very uniform. Natural products that reach this level are generally very rare. If multiple rubies and sapphires are put together, the color purity of each synthetic product is basically the same, while each natural product is different from each other.

2. Observing with a dichroic mirror, since most of the synthesized products are produced by Werner's Leaf method, the crystals synthesized by this method will crack along a long axis direction due to the release of internal energy, and most of the finished gems are parallel to the optical axis, so the synthesized products can see dichroism from the mesa direction; However, when cutting and grinding natural products, the mesa is usually perpendicular to the optical axis, so it is generally difficult to observe dichroism from the mesa.

3. Ultraviolet fluorescence test For rubies, the ultraviolet fluorescence of synthetic products is stronger than that of natural products, and many of them have the same fluorescence. Natural products are different from each other.

4. Magnification inspection is the most meaningful. Natural products have various mineral inclusions, and synthetic products have unique internal characteristics. For example, the synthetic products produced by Werner's method have curved growth lines, shapes like spiral patterns of records, and iconic features such as bubbles; The synthetic products produced by flux method will contain inclusions such as platinum flakes, feathers and flux droplets, but it is difficult to observe them. Hydrothermal synthesis products include alloy inclusions, nail inclusions, serrated, wavy and dendritic inclusions. Many synthetic products are flawless inside.

5. Large instruments, such as infrared spectrum and Raman spectrum, can detect the composition of precious stones, thus distinguishing natural products from synthetic products.