Spinel Gemstone Information

Mahenge Spinel

Spinel is a favorite of gem dealers and gem collectors due to its brilliance, hardness and wide range of spectacular colors. In addition to beautiful rich reds, spinel can be found in a range of beautiful pastel shades of pink and purple. In fact, the main thing holding back greater recognition for spinel is rarity. Fine spinels are now more rare than rubies. Paradoxically, they are also more affordable: in the gem world, too rare can be a drawback because so few people even get a chance to grow to love certain gem varieties.

In recent years spinel prices have begun to steadily increase as it has become better known and appreciated among gem collectors. Spinel is only slightly softer than corundum, and like it has no cleavage and is among the most durable of all gemstones. Diamond is the hardest of all substances (10) in the gemstone world; next in line are ruby and sapphire (both 9 on the hardness scale), followed by spinel (8). Because of this, spinel is perfect for all jewelry uses, including rings which are worn daily.

The prices and value of spinel can vary tremendously, depending on the size and quality of the gemstone. Pure reds and fine pinks are the most valuable colors, and the recently discovered neon pink-reds from Mahenge, Tanzania are among the most valuable of all colored gems. Secondary hues of brown or gray tend to lower the value of spinel. Clean and well-cut gems are always desirable, but minor inclusions are acceptable if they don't detract from the beauty of the gem.

Why Buy Loose Gemstones Instead of Pre-Set Jewelry?
There are many reasons, but mainly it comes down to value and choice...

When buying gemstone loose instead of a pre-set stone, you can be sure that you are getting the best value for your money. Loose gemstones are less expensive, a better value, and you can really see what you are paying for. The most important part of getting the right price and finding the best value is to first see what you're getting. A jewelry setting will hide the inclusions inside a gem, and can deepen or brighten its color.  With a loose stone you can much more easily inspect the gem and see it for what it really is. In this way you can get a better idea of its true worth and be sure you are paying a fair price.

The second advantage of buying a loose gemstone is choice. You are free to pick the exact color, cut, shape and variety of the stone for the setting of your dreams, be it yellow gold, white gold, platinum or silver; prong set or bezel set with diamond accents. You can experience the joy of creating your very own, one-of-a-kind jewelry design. Choose from a variety of jewelry settings and styles to create a completely original presentation that will perfectly suit your individual gemstone. Spinel makes stunning jewelry!


Burma Spinel Ring   Purple Spinel Ring   


Origin Myanmar (Burma), Sri Lanka, India, Madagascar, Vietnam, Tanzania, Russia, Canada and the U.S.A.
Color Red spinel, pink spinel, violet, blue spinel, green, aqua, orange, yellow, brown, and black. Rarely white or colorless.
Refractive Index 1.712 - 1.717, normal. Reds may go up to 1.735 and blues to 1.747
Chemical Composition  MgAl2O4
Hardness 7½ - 8
Density 3.5 - 4.1
Crystal Structure Cubic

Spinel is in the "aluminium oxide" mineral family of corundum. Spinel is found primarily in metamorphic rock, and as a primary mineral in basic rock. Spinel is also found in igneous and carbonate rock. In molten rock or magma, the absence of alkalis (sodium hydroxide or calcium hydroxide) prevents the formation of feldspar. If aluminum oxide is present in the magma, corundum (ruby) will form or the aluminum oxide will combine with magnesium to form Spinel. Ruby and red Spinel derive their coloration from the same Chromium Cr(3+) ion plus trace amounts of iron, manganese, and zinc. This is why spinel and ruby are often found imbedded in the same matrix. 

Spinel has a hardness of 8.0 on the Mohs scale. The durability of Spinel is excellent. Spinel has a high refractive index and is described as transparent to opaque with a vitreous to dull luster. Spinel has a refractive index of 1.712. 

The refractive index (RI), measured using a refractometer, is an indication of the amount light rays are bent by a mineral.  Birefringence is the difference between the minimum and maximum RI. When birefringence is high, light rays reflect off different parts of the back of a stone causing an apparent doubling of the back facets when viewed through the front facet. 

Most gems have a crystalline structure. Crystals have planes of symmetry and are divided into seven symmetry systems. The number of axes, their length, and their angle to each other determine the system to which a crystal belongs.  The crystal structure of spinel is isometric, and its crystal habit is octahedral or twinned octahedral (macles) and to a lesser extent, cubic or dodecahedral.  


Red is the most valuable color, followed by orange red, pinkish red and purplish red.  As the brightness of the color drops the price falls.  Of particular interest is a vivid hot pink with a tinge of orange that is mined in Burma that is one of the most spectacular gemstone colors in any gem species. The recently discovered neon pink-reds from Mahenge, Tanzania are rare and sough after by collectors.  Spinel also comes in beautiful blues which are sometimes called cobalt spinel, but these are also very rare. Star spinels are known, but extremely rare.

A fine deep raspberry red spinel is mined in Tadjikstan, a part of the Soviet Union. While the material is very beautiful, unfortunately this deposit produces only very small quantities of gems.


Spinels are cut mostly in ovals, cushions, rounds, trillions and pears.  Spinel is rarely found in calibrated sizes due to its rarity. 



Nearly all spinel gems are natural and untreated.  Usually color and clarity are already good in the crystals as mined, so little if any Spinel is treated to change its color, or improve its clarity.

AJS Gems fully discloses any and all treatments to our gemstones.

Most gem grade Spinel comes from Sri Lanka, particularly in Ratnapura, and from Mogok, Myanmar (Burma). The highest quality transparent blood-red "ruby spinel" and hot-pink spinel has come from the Pein Pyit (Painpyit) mine, Bawpadan mine, Inn Gaung Pyant mine, and Pingutaung mine in Mogok, Upper Burma (Myanmar) although these sources are rapidly being depleted. Other significant sources are located in the Mong Hsu stone tract, Myanmar.
In addition to Burma, spinel is mined in Sri Lanka, Tanzania, Vietnam and Tadjikstan, part of the former Soviet Union. Ambatomainty, Madagascar has produced large clusters of black crystals.  Recent discoveries in the Tundru region of Tanzania in East Africa have produced some beautiful sapphire and teal colored blue spinels - in these deposits, sapphire and spinel occur together and sometimes require gemological analysis to separate. The rare neon pink-red spinels from Mahenge in Tanzania are regarded by gem dealers as among the finest spinels ever discovered.
Spinel has also been found in Canada, in Ross Township, Renfrew Co., Ontario. In the U.S., the finest crystals came from a limestone belt streching from Sussex Co., New Jersey to Orange Co., New York. Those areas include Sparta and Ogdensburg, Sussex Co., New Jersey, together with Amity, Edenville, and Warwick, Orange Co., New York.  Spinel was also found at Bolton, Worcester Co., Massachusetts, and opaque blue crystal clusters occur in Lewis and Clark Co., Montana.
Due to its high weather resistance, spinel is principally found as crystal pebbles in secondary placer deposits.

Some of the world’s most illustrious “rubies” are actually spinels...

One of these is the Black Prince’s Ruby, a polished but unfaceted red spinel that weighs about 170 cts. It appears in historical records dating back to the 1300s and is a central stone in the British Imperial State Crown.

One of the most fascinating spinels in the world is the "Timur ruby" which is a red spinel weighting 361 carats, that is cut in cabochon and named after Tamerlain, the Tartar conqueror, who was one of his owners.
This stone has the names of its former owners engraved upon it, and some of them are the same with previous owners of the famous Kohinoor diamond.  The Tamerlain is now owned by Queen Elizabeth of England.

A faceted red spinel of more than 400 carats belonged to Empress Catherine II of Russia, and is now part of the Russian Treasure in the Kremlin.

Spinels were most often referred to as "balas rubies", name which may have referred to their country of origin, either Badakshan in Afghanistan or the Balaksh region of Sri Lanka.

The origin of the name spinel is unknown. It may be a derivative of the Latin word "spinella" or from a Greek word meaning spark, in reference to the bright red or orange color of some crystals.

Spinel is thought to protect the owner from harm, to reconcile differences, and to soothe away sadness.

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