Like all gemstones, the value of red spinel (often called ruby spinel), depends upon clarity, color, rarity, cut and size. Red spinels also present some other factors when determining their market value.
Spinels come in a variety of colors, ranging from dark blue to flaming orange. According to Gemselect.com, red spinel is the most sought after by collectors because of its striking resemblance to ruby.
In the gemstone world, rarity does not always mean more valuable. In fact, because of their relative scarcity, red spinel does not have a high market value, according to GemStone Systems. Because the supply is so low, the demand also remains low.
Spinels also have a reputation of being grown synthetically because of their status as the September birthstone. As a result, many collectors shy away when they hear "spinel."
Spinel has long been a favorite of collectors for a number of reasons. The brilliance of the stones, their hardness (slightly less hard than rubies), clarity (they have fewer flaws than rubies) and rarity make them a favorite of jewelers.
Red Spinel Value
All of these factors contribute to the value of red spinel remaining relatively low for a gemstone. A clear stone with a good cut, color and carat weight will go for anywhere from $20 to $200 per carat, as of 2010. Ruby spinel continues to remain one of the most undervalued of the fine gemstones, according to GemSelect, which sells loose gemstones online.