These are typically thought of as being darker in tone than Burmese rubies and often brownish-red to dark purple-red. The Thai ruby makes up the bulk of the world's production and comes in all qualities.

There is a price premium placed on both the size and shape of the ruby. A good rule of thumb for the price per carat is the larger the stone, the greater the price per carat. This is not an exponential scale. A three-carat stone, of equal quality, will be about four times the price of a one-carat stone and twice the price of a two-carat stone. Shape also plays an important factor in pricing. The oval and cushion shaped stones bring a higher price per carat than other cuts of equal quality and weight. Generally, these shapes allow the cutter to get the most brilliant gemstones with the greatest weight recovery. For fine stones, the marquise is seen as a novelty cut and usually used only when the rough dictates the cut for the best weight retention. Emerald cut, with the pavilion cut in long rectangle "step" facets, does not bring out a ruby's brilliance as the oval and cushion shapes.