da sapere — June 18, 2020 at 5:00 am

In jewelry beware of false friends




In jewelry beware of false friends. Or rather, do not buy stones that have different value, but a similar appearance. Similar, but not the same. Yet, in the misunderstanding there have falls for not only authoritative gemologists, but also customers willing to pay figures with many zeros and even crowned heads. Do you want an example? Numerous precious stones belonging to the treasure of Tsar Peter I of Russia, believed to be rubies for a long time, were later classified as rubellite. The same gem, the ruby, has also deceived the royals of London: the so-called Ruby of the Black Prince of about 170 carats mounted on the British imperial crown is not a ruby, but a spinel, placed near the Cullinan II diamond, this authentic.

Al centro della corona il Rubino del Principe Nero, che in realtà è uno spinello
Al centro della corona il Rubino del Principe Nero, che in realtà è uno spinello

But how can such a sensational exchange of precious stones happen? Well, it was once easier: gemology was not a developed science and there were no instruments capable of measuring the light waves refracted by the stones used in jewelry. Even today, however, many vintage jewels may have mounted stones that do not correspond to those attributed. And, therefore, the value of the jewel can change dramatically. In short, beware of false friendships: as in life, even for jewelry they can be dangerous.

Spinello di 8 carati
Spinello di 8 carati

Ruby and spinel. Both are red stones, although the spinel can also take on other shades. The spinels that have clarity and transparency of gems resemble ruby ​​and sapphire. Not only that: it 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 extracted in Tanzania.
Rubino sangue di piccione, non scaldato
Rubino sangue di piccione, non scaldato

Ruby and rubellite. Rubellite is another red stone, which can have an intense hue similar to that of certain rubies. It is, however, a variety of tourmaline. Rubellite was already known by the ancient Romans and often the gem was confused with garnets and spinels. The great diffusion in the West occurred at the beginning of the seventeenth century after the importation by the Dutch from Sri Lanka. And today: in 1998 a large tourmaline mine was discovered in Nigeria and rubellite invaded the jewelers.
Rubellite con tonalità lampone
Rubellite con tonalità lampone

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

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. Zircons are natural stones. They may have different colors, but in the colorless variety it is very similar to diamond. Zircon, in fact, has a very high refractive index, lower only than that of the 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.
Uno grande zircone grezzo
Uno grande zircone grezzo

Emerald and demantoid garnet. They are two green stones. Demantoid garnet, just like emerald, takes on a green hue due to the percentage of chromium and iron, which lead to bright green hues or more tending to green-yellow, also green tending to blue. Another garnet variety, tsavorite, also has a green hue that can be mistaken for emerald. In fact, many jewelers combine the two stones on the same jewel to lower the cost.
Orecchini pendenti con granato demantoide
Orecchini pendenti con granato demantoide

Topaz and quartz. Sometimes white or lightly colored topaz on the yellow is exchanged for smoky or citrine quartz. Obviously a simple quartz costs less than topaz.
Pezzo unico. Anello con citrino lemon e zaffiri
Vanessa Martinelli, pezzo unico. Anello con citrino lemon e zaffiri

Collezione Petra, collana  in bronzo con topazio giallo by  Gaia Caramazza
Collezione Petra, collana in bronzo con topazio giallo by Gaia Caramazza







2 Comments

  1. Buongiorno, ho lasciato un ciondolo in gioielleria per la pulizia. La pietra era un granatina ma al ritiro la pietra era completamente bianca tipo zircone. Mi è stato detto che era sporca… Ho risposto che un ciondolo identico era in a casa visto che si trattava in origine di un paio di orecchini. Come posso agire?
    Grazie

    • Ciao Patrizia, purtroppo senza un accordo con la gioielleria l’unica via è rivolgerti a un avvocato. Ma fai attenzione: è probabile che il costo della consulenza sia superiore a quello del gioiello e andare in causa giudiziaria significa aspettare anni… In ogni caso, non sottovalutare lo zircone, se fosse quello vero (puoi leggere un articolo su gioiellis.com): è un’ottima pietra. Nel caso specifico, però, potrebbe essere una pietra sintetica (cubic zirconia) che ha perso la colorazione artificiale. Ti consigliamo di fare una verifica gemmologica sulla pietra identica che ancora possiedi: è probabile che il mistero si risolva. Auguri!

Leave a Comment

Your email address will not be published. Required fields are marked *