Natural or man-made gemstones?

The world of minerals and crystals is a vast world, and unfortunately among the many wonders that can be found there, it is not uncommon to also encounter forgeries of all kinds.

Gemstones of natural origin are often treated artificially to make them more attractive on an aesthetic level or to resell them as other types of rarer and therefore more precious gemstones.

In other cases, however, a totally artificial original material such as plastic, glass or resin is sold as natural stone.

Below I will report the most well-known and frequent cases of forgeries and alterations on the market, with the hope that more knowledge and awareness can benefit and enrich everyone.

Although the difference is easily distinguishable with the naked eye, its imitation is also very common. 

Natural Malachite has regular brushstrokes, even very dark green streaks, but never black. It feels cold and heavy to the touch. 

Its imitation, on the other hand, is generally made of plastic, the streaks are irregular and flickering, and have a clear alternation between different shades of green and black . Being plastic you will notice that it is very light and never cold to the touch. If you think you own a fake Malachite and want to dispel any doubts, you can carry out two tests: bring it close to a heat source (if it is plastic it will behave as such) or scratch it with a metal point (if it is plastic you will observe that under the green layer , the material is actually white).

The natural Sunstone is extracted in different parts of the world and can appear with different shades of orange and degrees of transparency. These are varieties of feldspar (the same family as Adularia and Labradorite). Its peculiarity is the presence of micro lamellar inclusions of Hematite which generate a shimmering phenomenon.

Its artificial imitation is made of glass in which tiny metal fragments are embedded, but which are presented in a uniform way .

Opalite and Noble Obsidian

Opalite and Noble Obsidian are often found in tumbled form together with other natural stones, however it is simply coloured artificial glass in both cases. Often small air bubbles can also be observed inside, which are typical of the industrial production process.

Turquoise

Natural Turquoise is extracted in different parts of the world, and has a blue color with possible brown or black veins, often opaque, and is usually stabilized in color to prevent oxidation from altering its color from blue to greenish. 

It is one of the most imitated stones on the market. Its forgeries can be made by chemically dyeing porous stones such as Howlite or Magnesite, or directly with totally artificial plastics and resins. Also in this case it is therefore possible to test and verify the material with a heat source or a metal tip.

As for the Mojave Turquoise (or Copper, Oyster, etc.) in this case it is a mixture of pieces of Turquoise and other materials (natural and artificial) which are then chemically dyed and polished.

 

Citrine Quartz

Citrine Quartz is currently perhaps the most imitated stone on the market, because it is extremely rare and in great demand. 

What we now find on the market, characterized by a warm and intense color that can go from honey yellow to orange, with white and not very transparent areas, is actually Amethyst (also from the Quartz family) which has been heated to very high temperatures in specific ovens to alternate the color.

The natural Citrine Quartz has a cold yellow color, it can have darker but certainly not white areas, and usually has a high transparency. Nowadays it is extremely rare, most of the specimens left on the market are left raw and have decidedly higher than average prices.

 

Aura Quartz

The Aura Quartzes are tips of Hyaline Quartz exposed to very high temperatures (up to 900°) and chemically treated with different substances, usually metals, to give them opalescent colors of different shades and intensities.

 

Agate

Agate is a very abundant gemstone in nature, therefore it is usually not imitated with artificial materials, but very often it is chemically dyed to make it more "attractive". The colors found in nature (many!) are in fact generally very soft, while the dyed Agates have bright colors such as fuchsia, neon blue, etc.

 

Cracked Quartz

Also in this case it is hyaline quartz which is cracked to allow a chemical dye to penetrate and color the stone. 

 

Black Onyx and Obsidian

Black Onyx and Obsidian are also very often imitated (especially in beaded bracelets). In the case of black onyx, stones that belong to the same family as onyx are chemically dyed, such as agate or chalcedony, or artificial vitreous pastes are used directly. And this is often the case with Obsidian as well.

Natural Onyx is a variety of Agate with black and white bands. In the black parts, the color can be more or less intense, but it is rarely uniform. Natural obsidian, on the other hand, is more difficult to recognize if worked and smoothed, the advice is to buy it raw and go and look for those impurities and imperfections typical of a natural original material.

 

Amber

Amber is the resin emitted by conifers which subsequently fossilizes over time (even tens of millions of years) and in some cases solidifies, preserving plant, fungal or animal remains including arthropods and, much more rarely, vertebrates. Its color can vary from yellow to reddish to brown, and it is translucent. Unfortunately, it too is forged very frequently and it is almost impossible to determine its authenticity from a single visual examination. However, two types of tests can be performed. 

The first, useful if the Amber is not mounted on jewellery, is to immerse it in a glass of water saturated with salt. If our Amber floats it is natural, if it sinks then it is an artificial imitation. If, on the other hand, the Amber is already mounted on a jewel (and therefore it would sink in the glass anyway) you can try rubbing it hard with a cloth soaked in acetone: if it is natural it will not get damaged, the artificial one will.

 

Moonstone: Adularia or White Labradorite?

In this case we are not talking about forgeries or treatments, but about a name which refers to two different types of stones. With Pietra di Luna (Moonstone) we can refer to Adularia, characterized by a phenomenon called adularescence which consists of a slight superficial glow visible when the stone moves. But we can also refer to the White Labradorite (often called Rainbow Moonstone), a variety of labradorite that is extracted mostly in Madagascar. White Labradorite has more intense reflections and colors ranging from light blue to blue, yellow up to orange-reddish or purplish tones.