Corundum is a magnificent gem mineral, and one that’s been avidly collected for eons. The most famous corundum varieties are ruby and sapphire. Both are aluminum oxide minerals. But it’s the trace elements found in their makeup that contribute the color.
Corundum is very hard, ranking 9 on the Mohs scale. Only diamond is a harder substance. The hardness is the main contributor to its ability to take a high polish and be extremely reflective. And that’s exactly what jewelry lovers crave. While it can be translucent or, even opaque - and often is - the finest examples of corundum are transparent, giving off its luxurious color and brilliance.
What’s the Dif?
Ruby owes its coloration mainly to the presence of chromium. If you say sapphire, and you should say that only when the color of the corundum is blue - your sapphire has trace elements of iron and or titanium in its aluminum oxide makeup. But corundum also appears in a ravishing line-up of colors like yellow, orange, green, even purple and black. Those are properly referred to as fancy color sapphire.
Speaking of fancy, one of the most popular fancy colored sapphires is the pink variety. It’s simply a pretty stone, and the range of pinks can go from delicate pastel baby pink to exciting hot-as-fire pink, and even Padparadscha - that super-pricey orangey-pink stone. Industry pundits point to the high demand for natural pink diamonds - of which there a very few - as driving the interest towards delicate pink sapphires today.
Because diamond and corundum are close in hardness and several shades of fancy pink sapphire mirror the tints of pink diamonds - you’ve got a match made in jewelry heaven. The difference in price between fancy pink diamonds and fancy pink sapphire is enormous. Quantity and carat sizes are also much more available with pink sapphires - so there you go.
Since all of these corundum varieties are natural occurrences, like people, no two are exactly alike. Some corundum is bright red - and that’s ruby. But when it veers toward the pink tint - now we’ve got fancy pink sapphire. When the coloration is close, how do we make a separation? That’s the great conundrum in the gem world. In general ruby is more expensive than fancy pink sapphire; but maybe not in the case of Padparadscha fancy pink sapphire whose prices can get pretty steep.
A true red, even a crimson hue with a bit of an orangey secondary color will be sold as ruby. The straight lipstick reds and tomato-red tints are obviously ruby. Pigeon blood is used to describe top quality Burma ruby. But I suppose you’d have to get near an expired pigeon to understand the nuances of that exact tone.
On the flip side, a lighter toned pink corundum and those with a slight purplish-pink back color are definitely fancy pink sapphire. To split hairs, laboratories will tell you that the amount of chromium in red ruby can hover around .9% contrasted to below .5% found in pink sapphire.
Most commercial pink sapphire comes from Sri Lanka and Burma - but production from Tanzania and Madagascar is penetrating the market in volume too. The world’s finest ruby comes from Myanmar (Burma); but Thailand, Sri Lanka and Cambodia offer some spectacular specimens too.
Know Your Stuff, OK?
At the end of the day, most people can separate their hot pinks from their blood reds so that should help a consumer sort out for themselves if they are buying fancy pink sapphire or a ruby. So much of it is personal - and in the case of ruby and pink sapphire, its beauty and sometimes its moniker lie with the beholder.
Veteran jewelry appraiser Jo Ellen Cole has seen her share of both pink sapphires and ruby in her day. It’s only when the coloration is extremely close that it becomes an issue.
She weighs in, “the difference between pink sapphire and ruby is always subjective and the opinion really depends upon the buyer.” She recommends the consumer to know what they are buying - and enter the process with that bit of knowledge. “A well informed buyer can usually separate between the sales pitch and the reality of the subject stone. When the distinction is close, sending it to a top notch lab is a good move.”