Natural spinel has a long and glorious history. Often mistaken as “ruby,” it was treasured by kings and emperors who passed it down through the hands of many as spoils of war. The Gemological Institute of America (GIA) talks about the many colours of this unusual gem.
One of the most famous historic examples of spinel is the so-called “Black Prince’s Ruby”. This crimson-red gem, which is smoothly polished and roughly octagonal in shape, was probably mined in the mountains of Afghanistan. It first appeared in the historical records of 14th century Spain and was owned by a succession of Moorish and Spanish kings before Edward, Prince of Wales (the “Black Prince”) received the stone as payment for a battle victory in 1367.
Since then, many other English monarchs, including Henry VIII, have cherished the gem. It has outlasted them all, surviving fires, attempted theft and World War II bombing raids. It was ultimately set in England’s Imperial State Crown and is on display in the Tower of London.
Until the 1800s, when spinel was recognised as a separate gem species, it was often called “Balas ruby” and found in present-day Badakshan in northeastern Afghanistan. Spinel’s colour can equal ruby’s red and though it has long been undervalued, it is a gem that can stand on its own merits.
Spinel possesses the heritage and pedigree to be one of the finest gemstones, but few consumers are aware of it. Many people, if they’ve heard of spinel at all, think of the synthetic version of the stone that imitates better-known gems like aquamarine or peridot in birthstone jewellery. The reason for spinel’s lack of visibility as a mainstream gem is that the supply is adequate only for the smallest of markets. If supplies improve, spinel could easily be promoted to a wider audience.
Spinel offers a wide range of hues from orange to intense “stoplight” red, vibrant pink, and all shades between purple, blue and violet through to bluish green. Natural red or pink spinel can be an effective alternative for other, more costly coloured stones such as corundum’s superb reds and pinks. Unlike ruby or emerald, spinel is rarely treated, which is an important distinction for many informed consumers.
Some spinel colours are rarer and more valuable than others. In general, red spinel is the most desirable, followed by fine cobalt spinel, then vibrant hot pink and vivid orange stones.
Red spinel ranges from orangy red to purplish red, with pure red to slightly purplish red hues of medium to medium-dark tone considered the finest of all.
A top-quality 5-carat red spinel might be valued at a tenth of the price of an equivalent quality ruby. A fine 5-carat pink sapphire will usually be valued around two to three times the price of a pink spinel of equal quality.
Purple, reddish purple and violet stones are valued much less than pink or red ones, typically around half of a pink spinel of similar quality.
Blue spinel ranges from violet blue through very slightly greenish blue hues and tends to be less attractive and less in demand than other rarer colours. The majority of stones have low saturation, and the blue hues take on a distinctly greyish look. The best blue spinel colours parallel blue sapphire, with violet-blue to pure blue hues in medium to medium-dark tones being most valued.
Because of the scarcity of spinel on the market, most rough is cut in free sizes instead of calibrated cuts. Prices rise sharply for fine red, pink and blue stones larger than 5 carats because they are generally in short supply.
Sources and Synthetics
Besides historical sources like Sri Lanka and Afghanistan, the Pamir Mountains in Tajikistan in Central Asia produce large, fine spinel crystals. Other places, like Myanmar’s Mogok region, which is famed for its rubies, also produce equally fine red and pink spinel, as well as a range of other colours. Here, as well as in other deposits such as Vietnam’s Luc Yen Valley and Pakistan’s Hunza Valley, corundum and spinel occur together in marble, and are found together in nearby alluvial deposits. In some places, spinel is more plentiful than ruby.
Africa has great potential as a spinel source. In Tanzania’s Morogoro region, red spinel is found along with ruby. Although the Ilakaka area of southern Madagascar is known for blue and fancy- coloured corundum, it also produces spinel in a range of different hues. About half of the stones recovered from this source are purplish violet to bluish violet with a high proportion of violet to greyish violet, or lavender stones. The rest are violet-blue to blue and purple to reddish purple. Only a small percentage, perhaps as low as 5%, are red, pink or orange.
Because natural spinel is rare and synthetic spinel has been produced for years, many people have never seen the natural stone. Researchers at the start of the 20th century who were trying to grow synthetic blue sapphire produced synthetic blue spinel by accident.
Since then, synthetic spinel has been commonly used as a substitute for sapphire, zircon, aquamarine, peridot and other natural gems.
Synthetic spinel is also manufactured into triplets. A synthetic spinel triplet consists of two layers of colourless synthetic spinel joined with a thin layer of coloured cement. This imitation is manufactured in emerald, peridot and amethyst colours – otherwise difficult to produce in synthetic spinel and corundum – for birthstone jewellery, class rings and other pieces.
How to Care for Spinel
Because spinel is more resilient and tough than many other gems (except corundum or diamond), it can be cleaned in an ultrasonic cleaner or steam cleaned. You may prefer, however, to simply use a damp, soft cloth or a soft bristle toothbrush to clean your spinel jewellery pieces.