Iolite Gemstone | Iolite Stone – GIA Iolite displays different colors when viewed in different directions Iolite is usually faceted to highlight its transparency Iolite’s finest blue color can rival tanzanite’s vivid hue Iolite’s pleochroism can be a challenge for cutters The mineral cordierite is known as iolite in the jewelry industry
Tanzanite Description - GIA Tanzanite's appearance is influenced greatly by its pleochroism, which is the ability of a gemstone to show different colors when viewed in different crystal directions
Iolite Description - GIA This silicate of aluminum, iron, and magnesium has two distinctive features—a beautiful, violetish blue through slightly violetish blue hue derived from iron and a striking, eye-visible pleochroism
Pleochroism in Faceted Gems: An Introduction - GIA In biaxial gems, pleochroism is displayed in a manner similar to that of uniaxial gems, except that there are three different pleochroic directions (X, Y, and Z) instead of just two
GIAs Gübelin Gem Project: Tourmaline Among the many varieties of elbaite tourmaline are verdelite (green), indicolite (blue) and rubellite (red) Some tourmaline specimens display multiple colors Optical effects include pleochroism (a change of color when the gemstone is rotated) and chatoyancy (a “cat’s-eye” seen in reflected light)
Iolite Quality Factors - GIA Iolite possesses two distinctive features—a beautiful, violetish blue through slightly violetish blue hue derived from iron and a striking, eye-visible pleochroism