(Spanish) Royal Collections has just presented its latest acquisition, the ‘Malaga’ citrine quartz, the largest cut citrine ever seen, weighting 2,200 carats, or 440 grams –nearly one pound of gemstone!
‘Malaga’ will be on show at the gems and natural science museum Art Natura, in Malaga city –southern Spain-. ´This museum will hold the world largest collection of gemstones, and will open its doors in 2011.
Despite of its size, ‘Malaga’, this big gem, renders an exellent clarity, since it is almost free of inclusions, and its color is reportedly absolutely natural, with no treatment or enhacement whatsoever.
It is known that most citrine quartz available in the market comes from heated amethysts, in particular amethysts which have a high content in Iron III as an impurity in their crystal lattices. This kind of heat treatment –at about 450ºC- induces a change in the Iron oxidation state, which consequently brings about a change in the color of the crystal: from vilolet to an orangish yellow.
If the original amethyst crystal is overheated, say 500ºC, the final color deepens to a brownish orange. These stones are commercially known as Palmeira Quartz.
If the treatment is further overdone, above 600ºC, the amethyst turns into a lifeless translucent to opaque whitish crystal, although sometimes this mistake is cut in cabochon and sold as Moonstone.
Fortunately, there are natural exceptions to all of the above, and Royal Collections’ ‘Malaga’ citrine quartz is one of them, a big and beatiful one, that will add to the Special Exibition Gems collection. This collection -that the one who is writing is eager to see- holds 24 magnificent gemstones deemed unique in the world due to their out-of-the-ordinary size and gemmological quality.