Historically, red spinels have been incorrectly labeled as rubies. But it's quite understandable how this happened as:

1.) Spinels are usually found in the same places where corundum is found; with ruby being the red variety of corundum. In fact spinels are often used as indicator stones by sapphire miners when looking for new sites as they occur together quite commonly.

2.) They have similar qualities in that corundum and spinels are hard minerals. And when faceted gives a similar sharp brilliance. There are blue spinels as well and some outstanding samples intersected with the colors of blue sapphires (also corundum).

3.) Basically anything red was labeled as rubies back in the day.

Today, however, gemology has allowed for clear separation/identification of these two gems. And I happen to love spinels because it comes in these moody shades. Yes, exceptionally rare ones are red or sapphire-like blue. But they also come in bright pinks, deep purples and deep greens. Transparent, clean, faceted spinels are really fine examples of colored gems and posses an almost diamond-like brilliance. Plus they're never really treated to enhance their colors or clarity in any way.

Inset are earrings and a necklace of multi-colored faceted spinels with round brilliant diamonds set in white gold.