Spinel is a magnesium aluminum oxide mineral that with the inclusion of other elements, produces color variations that span the spectrum and can produce a variety of beautiful, sought-after stones. It is distinguishable by its hardness and its isometric crystal habit, forming octahedral, dodecahedral, or cubic crystals. It is often and historically confused for ruby or sapphire, though it is slightly softer, ranking 7.5 to 8 on the Mohs scale. Spinel typically is found within igneous and metamorphic environments such as in marble or dolomite that have undergone contact metamorphism or as irregularly shaped grains within igneous rocks. Spinel is also found within alluvial deposits due to its high tenacity and ability to withstand chemical and mechanical weathering. This allows the spinel crystals to loosen from their host rock and travel downslope through mass wasting where their high specific gravity offers collections of spinel within the alluvial deposits. This is important to note because these alluvial deposits have been worked for over 1,000 years by miners in search of this beautiful stone. Historically, spinel has been around for generations and is sometimes referred to as “balas rubies”, for their similarity to a ruby. Adorned on England’s Imperial Crown is a 170-carat spinel gem that is called the Black Prince’s Ruby, one of the most famous and largest uncut spinels in the world. This gem has been passed down through European royal lineage, first appearing in fourteenth-century Spain. It was owned by Moorish and Spanish kings before Prince Edward of Wales, the “Black Prince”, was awarded the stone in 1367 as payment for battle victory. The Timur Ruby, another gem that is part of the British Crown Jewels, is actually a 361-carat spinel as well. The differentiation between spinel and ruby was historically difficult without scientific equipment, and it wasn't until 1783 that a mineralogist distinguished that they were indeed two different minerals. Spinel is actually a rare mineral, rarer than sapphires and rubies. Although its price point and popularity as a gem sits lower, spinel may be a good candidate for the title “history’s most underappreciated gem” according to the GIA, and a smart one to keep your eye on as its value might increase in the future. Most gem grade spinel comes from Burma and the original spinel gems came from Afghanistan, while Thailand, Sri Lanka, Vietnam, and Pakistan are other large exporters of this stone. Vietnam, Tanzania, Brazil, Kenya, Russia, Canada, parts of the US, and Madagascar are other sources of spinel.
