nature
Opulent PRECIOUS OPAL IS COUNTED AMONG THE BEST OF GEMSTONES, BUT IT IS QUITE UNLIKE ANY OF THE OTHERS IN THAT IT IS NOT A CRYSTAL
O
rdinary opal is in fact a very common mineral, and is a solid jelly with little or no crystalline structure. Precious opal, however, has a very special structure of tiny spheres about 500 nanometers in diameter, stacked in a 3-dimensional lattice. This measurement is of the same order of size as the wavelenghts of visible light, so this structure has the power to split white light into its spectral colours. The result is that a good precious opal will show flashes of intense colour when it is moved in a strong white light. The colour seen depends upon the exact size of the spheres.
So how did the opal acquire a dismal reputation for ill-fortune? In France, you never see opals in jewellers’ windows, and the jewellers I have chatted to say they will set an opal if asked, but would never willingly handle such an unlucky gem. In England also, there is a suspicion hanging over opals, and many people refuse to own one.
The non-crystalline nature of opal means that its properties are very different from other precious gemstones. It is noticeably As you can imagine, the conditions for this softer even than emerald, structure to form are very rare, and and so can scratch if worn precious opal is hard continuously. It to find. In antiquity contains water in most of the stones They were regarded its structure, and came from the east, is thus susceptible as bringers of good and were fabulously to changes in fortune and protection costly. It is told that a humidity, so some Roman called Nonius, against plague opals can actually who had a beautiful swell or contract in opal the size of a wear. This means that the stone’s walnut, treasured it so much that when setting must be flexible enough to Mark Anthony tried (rather aggressively) allow for this, or the stone can to buy it to give to Cleopatra, Nonius fled crack or fall out spontaneously. Rome, leaving his position and his wealth behind, just to protect his opal. Early jewellers were unaware of the opal’s special requirements, and Opals were prized as second only in value there are many stories about very and prestige to emeralds in the ancient expensive opals being ruined in setting. world. They were regarded as bringers of This would result in a financial loss, but if good fortune and protection against you were setting an opal that belonged to plague. Napoleon 1st gave a splendid opal the king you could lose your head as well! to Josephine. It showed predominately red So it is generally agreed in France that the fire, and was probably the first opal to be jewellers got together to spread the rumour given a name: The Burning of Troy that opals were accursed gems, to avoid (L’Incendie du Troie). Sadly, this opal is having to work on them. This may have now lost.
38 etcetera
