Pure spinel is white, but impurities give it a wide range of colors. Almost all colors are used in jewelry, but the most valuable and popular color is the deep red. These red gems closely resemble rubies, and the two may be difficult to distinguish. In fact, until the late 19th century, there was no distinction between ruby and red spinel, as they look identical and are found in the same localities. Nowadays, distinctions can be made through hardness and x-ray tests. Many famous old "rubies" were found to be Spinel. The enormous "ruby" that forms the centerpiece of the royal crown of England (the Black Prince's Ruby) was determined to be spinel.

Spinel is easily synthesized, and can be made into any color by adding impurities. It is made to resemble gems such as diamond, sapphire, and zircon. When purchasing spinel gems, one must be careful to make sure the spinel is natural and not synthetic. Most colorless spinels on the market are synthetic, as are some red ones.

USES
Spinel is cut into gems for use as jewelry. The deep-red variety, known as ruby spinel, is the most prized form. The opaque, black variety, known as pleonast, is perhaps the most popular black gemstone. Spinel is also cut as cabochons, and occasionally exhibits weak asterism.
Spinel naturally occurs as octahedral crystals. In well-shaped red crystals, the gem cutter may decide to even out the crystal, making it a perfect octahedron. These "crystals" may be worn in jewelry without any further faceting.

VARIETIES
Ruby Spinel - ruby-red variety of Spinel
Rubicelle - yellow to orange variety of Spinel
Balas Ruby - pink to pale red variety of Spinel
Almandine Spinel - violet variety of Spinel
Blue Spinel - light to dark blue variety of Spinel
Pleonast - black variety of Spinel
Picotite - brown variety of Spinel
Gahnite or Gahnospinel - greenish or bluish, zinc-rich variety of Spinel *
Sapphire Spinel - false name describing blue spinel

SYNONYMS
Spinell is a synonym of spinel
Spinel ruby is a synonym of ruby spinel
Piconite is a synonym of picotite
Flame Spinel is a synonym of rubicelle
Pleonaste is a synonym of pleonast

SIMILAR GEMSTONES
Ruby spinel can be identical in appearance to ruby. Only optical properties and hardness can distinguish the two. Blue spinel may resemble zircon and topaz; pink spinel may resemble morganite, topaz, tourmaline, kunzite, and rose quartz; purple spinel may resemble amethyst.

ALSO SEE

• The mineral Spinel
• Ruby

PICTURES

Special thanks to Gem Hut for most of our gem images. The gems displayed or others like them can be purchased through GemHut by clicking the link below each picture.

Picture: Ruby Spinel (bright red Spinel)
Size: 1.92 ct.
Cut: Oval
Collection: Gem Hut

Picture: Ruby Spinel (bright red Spinel)
Size: 1.48 ct.
Cut: Cushion
Collection: Gem Hut

Picture: Ruby Spinel cabochon
Size: .87 ct.
Cut: Cabochon
Collection: Gem Hut

Picture: Almandine Spinel (Purple Spinel)
Size: .94 ct. (both gems)
Cut: Trillion
Collection: Gem Hut

Picture: Balas Ruby (Pink Spinel)
Size: 2.05 ct. (both gems)
Cut: Oval
Collection: Gem Hut

Picture: Colorless Spinel
Size: .81 ct.
Cut: Trillion
Collection: Gem Hut

Picture: Transparent, dark Blue Spinel
Size: 7.79 ct.
Cut: Pear
Collection: Gem Hut

Picture: Pleonast (Black Spinel)
Size: 4.36 ct. (both gems)
Cut: Hexagonal
Collection: Gem Hut