Iolite is a popular and interesting gemstone. It has a pretty violet/blue color that is different from all other gemstones. It is sometimes referred to as "the water sapphire". Although the color is similar to tanzanite, it is one of the more affordable gemstones. Its hardness is 7 - 7.5 on the mohs scale, making it very wearable for jewelry. The refractive index is 1.52 to 1.57 with an orthorhombic crystal system. The major sources of quality iolite gemstones come from Sri Lanka, India, Madagascar and Burma. More information on iolite is available here. To view our finished iolite jewelry, click here.
| CHEMISTRY | (Mg,Fe2)Al4Si5O18 |
| SPECIES | Cordierite |
| CRYSTALLOGRAPHY | Orthorhomic |
| REFRACTIVE INDEX | 1.522 - 1.578 |
| HARDNESS | 7 - 7.5 |
| SPECIFIC GRAVITY | 2.53 - 2.78 |
| BIREFRINGENCE | 0.008 - 0.012 |
| CLEAVAGE | Distinct 1 |
| HEAT SENSITIVE | No |
| WEARABILITY | Very Good |
| SPECIAL CARE INSTRUCTIONS | None |
| ENHANCEMENTS | None |
Jewelry designers have long searched for an affordable gem to complement the rich blues so prevalent in fashion, from denim to velvet. They found it in iolite, an unusual gem that offers rich blue color that won't break the bank. Named from the Greek ios, or violet, iolite at its best is a rich violet blue that might remind you of better-known gems like tanzanite and sapphire. Iolite is also known as dichroite and cordierite.
Although it is still not well known, iolite has a long history. When Leif Eriksson and the other legendary Viking explorers ventured far out into the Atlantic Ocean, away from any coastline that could help them determine position, they had a secret gem weapon:
The Viking sailors used thin pieces of iolite as the world's first polarizing filter. Looking through an iolite lens, they could determine the exact position of the sun on cloudy days, and navigate safely to their new worlds and back. Since those Vikings most probably found the American coastline long before Columbus, iolite achieved a practical importance that easily compensates for the fact that it produces a blank page in the books of myth, wisdom, the zodiac scheme or the relation between planets and mankind.
Iolite is usually a purplish blue when cut properly, with softness to the color that can be quite attractive. The favorite color is that pretty, violet blue that is unlike other gemstones. Pleochroism is very pronounced in iolite and is seen as three different color shades in the same stone. In the viewing an iolite stone, the colors violet blue, yellow gray and a light blue can be seen, all a result of pleochroism. Its hardness of 7-7.5 makes it a desireable jewelry stone, though the presence of cleavage must be taken into account and some care exercised, like protection from blows.
Many legends, beliefs and folklore surround the Iolite gemstone. Iolite is believed to be the gemstone of happiness and joy. It is also believed to posess Feng Shui properties that help build relationships with others. For people who believe in the special powers of gemstones, this gemstone is supposed to cure sore throat, varicose veins and various skin eruptions and blisters. We have already mentioned above, the special properties of Iolite that gave it the name of the 'gemstone of the Vikings'.
The main sources of Iolite are India, Sri Lanka, Mozambique, Zimbabwe and Brazil. The Vikings probably mined iolite from deposits in Norway and Greenland. Currently the gemstone is available in considerable quantities and this has resulted in Iolite having a moderate price tag. However larger sizes of good quality Iolite are beginning to show upward price trends and will therefore make good buys now.
Sinkankas lists the wholesale value of fine blue violet stones in the 1 to 5 carat range as $60 to $80 per carat and $100 to $150 per carat for stones 5 to 10 ct. He also notes that stones larger than 8 carats are rarely eye clean. Federman is more conservative, listing retail values as $100 and $150 per carat, respectively, for those size ranges. Writing in 1990 he reports that German cutters have been buying iolite rough in quantity to capitalize on an expected surge in popularity and price.