Information
INTRODUCTION SPINEL
Spinel is an important gemstone in its own right, though it is somewhat overshadowed by Ruby & Sapphire.It is of the cubic system and , consequently, singly refractive; an identifying feature. Deep red ,it is sometimes called ‘Balas Ruby’; a famous example is the ‘Black Prince’s Ruby’ set in the English Crown Jewels,which is ,in fact ,a Spinel. Deep reds command a high price, where as the paler shades of red, brownish and yellowish reds are much cheaper. Pale to deep blue, violet blue, purple and mauve are also important. It is hard , 8 on the Mohs scale of hardness,with a vitreous or glassy lustre,capable of a high polish.
COLOR, CLARITY AND CUT
Spinel Red, the finest colors tend to be similar to ruby, rich, intense red similar to that of a red traffic signal. However, Spinel tends to be a bit more of a brick red than Ruby (which is slightly more purplish). Like all gems, the most-highly sought are those whose color is intense, while being not too light or dark. Prices decline as the color diminishes into either light pinks or “garnety”reds. Orange Spinels can also be magnificent. Look for stones that are a rich orange without too many blackish overtones. Sri Lanka rarely produces blue Spinels colored by cobalt. Such “cobalt” blue Spinels are highly sought after by collectors. The best pieces are an intense blue unique in the world of gems. In addition to red, pink, orange and blue, Spinel is found in a myriad of other colors. These are generally termed “fancy” Spinels, and occur most often in shades of mauve, violet, purple and blue-green..In terms of clarity, Spinel is often cleaner than ruby. However, the very finest reds are so rare that some clarity defect is almost always present (usually fractures). Included crystals are quite common in Spinel. Many stones display natural iron-oxide stains in their fractures. Due to the octahedral nature of Spinel rough, the most common shape seen is the cushion. Rounds are also seen, as are other shapes, such as the emerald cut.
VALUE
Spinel has always resided in the shadow of ruby, with the result that prices are just a fraction of what the equivalent ruby would cost. Prices of intense cobalt-blue Spinels can rival, or even exceed, those for the finest reds. Because synthetic Spinels are often used for imitation birthstone rings, many people think “synthetic” when they hear the name “Spinel.” This is unfortunate, for a fine gem Spinel is one of nature’s most beautiful and rare treasures. Visit our dubai online shopping and we can assist you with the right information about the value of Spinel and about any other gold stones.
THE PROPERTIES OF SPINEL AND CORUNDUM IN COMPARATION
| Spinel | Corundum (Ruby & Sapphire) | |
| Composition | MgAl2O4 | Al2O3 |
| Hardness (Mohs) | 8 | 9 |
| Specific Gravity | 3.63 | 4.00 |
| Refractive Index | 1.718 | 1.762–1.770 (0.008) Uniaxial (–) |
| Crystal System | Cubic | Hexagonal (trigonal) |
| Colors | Near colorless, red, pink, orange, green, blue, violet, | All (except an emerald-green) |
| Phenomena | Star (4 & 6 rays), cat’s eye | Star (6 & 12 rays) |
| Handling | No special care needed | No special care needed |
| Enhancements | Generally none; occasionally oiling, dying | Various, including heat, heat + flux healing, surface-diffusion, irradiation, oiling, dying, glass-infilling |
| Synthetic available? | Yes | Yes |
ORIGIN AND IMITATION
Sources are many: Burma (Myanmar) ,Sri Lanka, Afghanistan, Thailand, Australia, Sweden, Brazil and the USA.Synthetic Spinel has been produced commercially for very many years. It is made in colours not usual for natural Spinel: blues simulating Aquamarine and Zircon, both showing strong red under the Chelsea Filter. It is also to simulate Alexandrite and ,of course, Sapphire. A colourless variety is produced to simulate diamond but is not very successful as it lacks the fire when brilliant cut, so is often cut as baguettes.
Having been treated as the poor relation of the ruby for very many years, Spinel is at last being appreciated for its natural beauty. This increased interest in the natural stone has led to arise in the output of synthetic red Spinel. This is probably also due to the increasing rarity and high cost of good Rubies, now the most popular investment gemstone (untreated of course).The new synthetic Spinels are more difficult to identify for the gemologist and impossible for the layperson.
FAME, NAME AND LEGEND
Spinel is believed to derive from the Latin word, spina, meaning “thorn,” perhaps in allusion to the pointed shape typical of Spinel octahedra. In the past, Spinel has been referred to as “balas ruby”.
