With some degree of irony, spinel can be considered as one of the "youngest" gems. The naked eye finds it difficult to distinguish spinel from a ruby and red spinel was long considered a ruby before science established a clear distinction between these two types of minerals. This resulted in much disappointment for many wealthy collectors around the world. However, this disappointment proved short-lived because they suddenly gained a very beautiful and rare gem instead of the coveted ruby.

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Spinel closely resembles corundum. In fact spinel is an oxide just like corundum in terms of its chemistry but also contains aluminum and magnesium – MgAl2O4. Corundum is colorless just as impurity-free spinel is. Spinel turns red due to the presence of chromium admixture. However, apart from the red, noble spinel in all of its shades can be dyed into any blue tone ranging from pale blue to intensive and deep blue with a light purple hint. There is also green spinel but the most valuable spinel has a red color.

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So far it is not known where the name of this mineral came from. However, there are two main versions of the Latin and Greek origin which best characterize this gem. It is called a "thorn" for the sharp edges of its natural crystals or a "spark" for the unique sharp and bright shine the polished gem acquires.

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RG Crystals offers lab grown and synthetic spinels, which are produced using the Czochralsky and Flame Fusion methods.