At one time this variety was known as hyacinth, although it did not match the description of hyacinth left us by Pliny the Elder. indeed, a number of orange-red or brownish red stones were called by this name until the knowledge of mineralogy, which began to be acquired in theeighteenth century, caused these names based purely on color to be abandoned.

Appearance Red—often brick or orange red, but sometimes even a violet red. Like all zircons, it has considerable luster, shown to advantage by the zircon cut (a modified form of brilliant cut) sometimes. used for these stones. Round or oval, mixed cuts with a brilliant-cut crown and step-cut pavilion are, however, more common, as they are with most other colored stones.

Distinctive features As always with zircons, the marked birefringence is a useful means of recognition. The color (with faint pleochroism) and luster can make red zircon look like some spinels and possibly garnets, but these gems are singly refractive. Marked birefringence also easily ily distinguishes it from corundum, in which the effect is much weaker. It has the physical properties of high zircon, with refractive indices above the range of normal refratometers. As with other zircons, however, it almost always has a highly distinctive absorption spectrum.

Occurrence Red or reddish zircon comes mainly from Sri Lanka, Cambodia, and Thailand.

Value it is more or less equal in cost to the best blue zircons, and is therefore not one of the highest priced secondary gems.

Simulants and synthetics These zircons are not sufficiently well known to be imitated. Red zircon is not produced synthetically.