kristin
08-04-2006, 10:34 AM
Iolite
Cordierite is better known by the trade name Iolite which comes from the Greek word for violet, “ion”. Iolite’s strong pleochroism makes it an effective light filter. Early Viking navigators used thin slices of iolite as glare-reducing filters to protect their eyes when they checked the sun’s position. Iolite rates a 7 to 7.5 on mohs hardness scale, but its toughness is only fair because it has a distinct cleavage in on direction. Iolite is not treated unlike some similar colored gems like Tanzanite, which is heat-treated to obtain its color. Iolite’s freedom from enhancement other than normal cutting and polishing is a good selling point for customers looking for an untreated blue to violet colored gem.
Cordierite is better known by the trade name Iolite which comes from the Greek word for violet, “ion”. Iolite’s strong pleochroism makes it an effective light filter. Early Viking navigators used thin slices of iolite as glare-reducing filters to protect their eyes when they checked the sun’s position. Iolite rates a 7 to 7.5 on mohs hardness scale, but its toughness is only fair because it has a distinct cleavage in on direction. Iolite is not treated unlike some similar colored gems like Tanzanite, which is heat-treated to obtain its color. Iolite’s freedom from enhancement other than normal cutting and polishing is a good selling point for customers looking for an untreated blue to violet colored gem.