In the world of colored gemstones, there are certain species and varieties that people consider to be collector's gems. This may have different meanings for some (possibly referring to high-end auctioned gems in some cases), but for many enthusiasts- a collector's gem is a species that has its own unique optical beauty, despite not always being used in main stream jewelry stores.
Today we'll look at one of these uncommon, yet beautiful collector's gems that you may or may not have seen in the Philippine jewelry circles. It's frequently seen by our gemological team during visits to international gemstone fairs in Hong Kong or Switzerland, but locally only very few brands seem to carry it in their jewelry designs.
Sphene, which is sometimes also called Titanite, is a stone with a dispersion rate greater than that of diamonds. What is dispersion you might ask? Well, dispersion rate actually governs the amount and intensity of the spectral color flashes you see when rocking and tilting your gemstone. Those sharp, crisp sparks of red, blue and green that a lot of people usually associate with diamond- this in layman's terms is called 'fire', but we refer to it as the dispersion of light.
This gem can be found in many colors, but its most popular hues are yellowish green and orangey brown. It's quite easy to recognise due to its strong fire display. Couple that with another interesting property; a very high birefringence. This specific trait splits incoming light rays into two, visibly observable by looking into the stone and seeing its inclusions or back-facets double. Sphene is considered a doubly refractive stone, and while many other stones also show visible doubling of interior characteristics, sphene's birefringence value of 0.100-0.192, makes its doubling one of the strongest in the realm of gemstones.
When buying sphene, always look for a good balance between fire, bodycolor and clarity. Sphene tends to have a lot of inclusions, which may seem larger or more plentiful than they actually are due to the effects of its strong birefringence. This stone, while not as popular as ruby or emerald, has its own indescribable appeal. You'd have to see it in person to really appreciate the elegant combination of traits that it possesses. Here at the laboratory, we have seen a few high-end jewellers and gem enthusiasts bring in specimens of faceted (fully cut) sphene for checking.
