Think in terms of cost per carat, not total cost.
Beware of "Total weight" signs in set rubies. Only pay for the weight of the stone
Rubies are dense stones. A one carat ruby may be smaller than one carat of another gem.

Of course carat weight is important for rubies, but only insofar as you need to know the price per carat. It is far more crucial to find a stone of pure color and good clarity in the price range you set. But a few ruby specific carat items of interest:

1. For stones between 1/2 carat and 1 carat, think in terms of cost per carat, not total cost. Rubies under 1/2 carat will likely be listed by millimeter size.
2. When comparison shopping, only consider stones of similar size, cut and overall quality. In other words, don't compare a 2 carat oval with a half carat round.
3. Corundum is far more dense than most gemstones, so a one carat ruby may be smaller than a one carat diamond.
4. You may hear "size" used in place of weight, it's common. But cut can have an illusory effect, a one carat ruby may look smaller than one weighing a little less.
5. Watch for rings or pendants with a "total weight" label. Ask the weight of the stone prior to setting.
6. It's always smarter to buy your quality gemstones unmounted.

Now that you've rooted out this bunch of carat facts, you can tell your jeweler to "show me the rubies."

Answer to quiz: c