Faceted oval gemstones cut from synthetic spinel. Pure spinel, magnesium aluminum oxide, is colorless, but small amounts of chemical impurities create myriad hues. The red variety of gem quality spinel has a specific name: ruby spinel. Spinel is produced synthetically in the laboratory by a variety of methods. The synthetic (man-made) material has properties nearly identical to natural spinel, but slightly different optical properties that allow for easy detection.