Gems that look the same

You can choose stones that look similar, but they aren’t the same (not even in price).

In jewelry, beware of false friends. There are stones that have different values, but a similar appearance. Similar, but not the same. Yet, not only authoritative gemologists have fallen for this misunderstanding, but also customers willing to pay high prices, and even crowned heads. Want an example? Numerous precious stones belonging to the treasury of Tsar Peter I of Russia, long believed to be rubies, were later classified as rubellites, a less valuable variety of tourmaline. The same gem, the ruby, even fooled the royals in London: the so-called Black Prince’s Ruby, weighing approximately 170 carats, mounted on the British imperial crown, is actually not a ruby, but a spinel, set next to the genuine Cullinan II diamond. In short, stones with the same color and quite similar. But one is worth more than the other.

Ruby and spinel. Both are red stones, although the spinel can also take on other shades, for example these stones can also be black. Many spinels used in jewelry have a color and clarity very similar to that of ruby ​​and sapphire (two stones that are varieties of corundum). Not only that: spinel is often found in deposits adjacent to those of these two most precious stones. In addition to the deep red spinel, there is also a raspberry-colored variety that is mined in Tanzania.

Ruby and rubellite. Rubellite is another red stone, which can have an intense hue similar to that of certain rubies. However, it is a variety of tourmaline, a less rare gem than rubies. Rubellite was already known in ancient Roman times and the gem was often confused with garnets and spinels. The great diffusion in the West took place at the beginning of the seventeenth century after the Dutch importation of the rubellite from Sri Lanka. In 1998 a large tourmaline mine was discovered in Nigeria and rubellite invaded jewelers.

Spinel and taaffeite. Between these two stones it is taaffeite that is rarer and more expensive. Taaffeite is named after its discoverer, the Irish Richard Taaffe, who in 1945 identified it as confused with spinel. Sent to London for analysis, it was identified as a new precious stone, unfortunately very difficult to find. Unlike spinel, taaffeite exhibits the property of double refraction which allows the distinction between these two minerals. It can have different colors, including red, violet and red, which make it very similar to certain varieties of spinel.

Diamonds and zircons. Attention, let’s not talk about cubic zirconia, which are artificial stones with a very low price and used for pendants and bijoux that cost a few tens of euros or dollars. Real zircons are natural stones. They can have different colors, often found in the blue hue, but there are also colorless zircons like diamonds. Furthermore, zircon has a very high refractive index, lower only than that of diamond, and for this reason it has often been mistaken for the gem it resembles. From a chemical point of view, however, diamonds and zircons are different: the former are made of pure carbon, the latter are nesosilicates.

Emerald and demantoid garnet. They are both green stones. The demantoid garnet, just like the emerald, takes on the green hue due to the percentage of chromium and iron, which lead to bright green shades or more tending to green-yellow, even green tending to blue. Another variety of garnet, tsavorite, also has a green hue that can be mistaken for emerald. In fact, many jewelers combine the two stones on the same piece of jewelry to lower the cost.

Topaz, quartz, aquamarine. Sometimes white topaz or topaz with faint yellow hues is mistaken for smoky or citrine quartz. Obviously a simple quartz costs less than topaz. In the blue hue, on the other hand, a pale-colored topaz can be mistaken for an aquamarine. The value of the two stones, however, is different.