Iolite: Catalina

Iolite is the gem-quality form of the mineral species cordierite. The colors of iolite range from dark sapphire blue to light blue-violet. The pleochroic properties of this gem give it a watery appearance and have earned it the nickname "water sapphire."

Fine gem quality samples of the mineral cordierite go by the name iolite, but this deep blue gem has been known by many names during the ages. Iolite was first described in 1809 by French geologist Louis Cordier. The name "iolite" comes from the Greek word for violet. This gem displays strong pleochroism, meaning that it appears different colors when viewed from different directions. Because of this, this gem was also once called "dichroite," from the Greek for "two-colored rock." Its pleochroism also earned it the nickname, "water sapphire." Like the ocean, the color of iolite can appear different shades at different depths. The color of the ocean off on the horizon doesn't look the same as it is does at the shore. Iolite too can seem a deep blue from one angle and nearly colorless from another. A cube cut from iolite will look a violet-blue, similar to a sapphire, from one side, clear as water from the other, and a honey yellow from the top. It is important to note that other than its blue color, iolite shares no relationship to sapphire. Because of its hardness and pleochroism, iolite can be one of the most difficult stones to cut. It must be cut in a certain direction to take advantage of the best color, which can be tough when the shape of the rough doesn't lend itself to cutting in that same direction.