As spinels are now considered an August birthstone, followed by sapphires in September, we wanted to take a moment to highlight and compare the amazing characteristics of both stones.

Both gemstones are incredibly popular, but their wide ranging color palette is becoming increasingly recognized to jewelry lovers and collectors. Although blue sapphires are more often associated with September, in reality all fancy sapphires serve as the birthstone for this month. This is also true for the seemingly infinite colors found in spinels. 

Red spinel was first discovered in the 9th century and popular in the Mughal Empire, they were often known as a “Balas rubies,” a name likely derived from the North Indian region of Balascia (or Badakshan.)  Confusion with corundum occurred for centuries, as both gemstones have been found in the same mining locations. Spinel’s popularity prior to the modern era dramatically changed when it was first synthesized at the beginning of the 20th century. This association, without question, damaged the reputation of spinel commercially. But in the past two decades that has changed, thanks in part to the discovery of the bright vivid pink/red spinels of Mahenge, Tanzania. 

Seen here, a 3-Stone Burmese Red Spinel Ring.

3.58 carat Tanzanian Spinel, displaying vivid pinkish-red color.

Spinel’s recent rise in notoriety was also aided by the discovery of cobalt spinel in Yên Bái Province, North Vietnam at nearly the same time as pink spinels of the Mahenge region.  The material discovered was a medium-light to medium-dark vivid blue, unlike the grayish blue spinel more commonly seen. 

Seen here, a 2.24 carat Cobalt Blue Spinel accented by Hauyne & Diamonds.

Long regarded as the jeweler’s gemstone, spinels prestige continues to rise commercially. Likewise, demand has increased for the various colors of corundum that were long overlooked in favor of the most popular colored gemstone in the United States: blue sapphire. More commonly referred to as fancy sapphires, their color occurs in the full range of spectral and mixed hues. This is true for spinels as well, with the exception of perhaps yellow. 

Seen here, a 4.10 carat yellow-orange sapphire, Ceylon, unheated.

Seen here a blue-green parti fancy sapphire.

When comparing these two gemstone gemologically there are distinct differences to consider. Sapphires are considered harder, as corundum is a 9 on the Moh’s hardness scale, only diamond is harder. Spinel is ranked as a 7.5 to 8. As such, both gemstones are tough and durable gems for regular wear. Both have high refractive indexes that give these gemstones lots of fire, but spinels are singly refractive, like diamonds, and are known for their dramatic sparkle. 

Seen here, a 2.41 carat Pink Sapphire Ring and a 2.36 carat Pink Spinel Ring.

Typically fancy sapphires will display more vivid hues, as deeply saturated spinels are less common. However, approximately 98% of sapphires are regularly heat treated to enhance their color and dissolve inclusions. Spinels are rarely treated in any way, and although their color is often modified by grey tones, collectors appreciate the natural nature of this gemstone. 

Grey undertones are visible in the variety of colors in this 4.15 carat Lavender Spinel design.

If you are after a phenomenal gemstone, sapphires can display both asterism and color change. Spinels however, can appear to color shift, but likely will not achieve the color change to the degree of corundum. 

Seen here two examples of Star Sapphires.

No matter your preference, at Omi Privé, we love celebrating the differences and wide range of colors of both sapphires and spinel!