Chemical Formula Mg2Al4Si5O18
Color Blue, Purple, Gray
Hardness 7 – 7.5
Crystal System Orthorhombic
Refractive Index 1.55 – 1.62
SG 2.6 – 2.7
Transparency Transparent to translucent
Double Refraction -0.01
Mineral Class Cordierite
Iolite is strongly pleochroic, and will exhibit a different color when viewed at different angles. In fact, it is the most pleochroic gemstone, with this effect being clearly noticeable on all transparent Iolite gemstones. A blue or violet-blue Iolite gemstone will become a duller gray or grayish-yellow when viewed at a different angle. For this reason, care must be taken by gemstone cutters to facet Iolite gemstones so that their colors are oriented with the intense blue or violet showing from the top.
Iolite is cut into gemstone facets and cabochons, and is used in all types of jewelry, especially rings, earrings, and pendants.
Water SapphireIolite gemstones are natural and not treated or enhanced.Iolite gem deposits are Madagascar, Myanmar (Burma), Sri Lanka (Ceylon), India, and Brazil.
Iolite TREATMENTS AND ENHANCEMENTS
Sapphire – Lacks dichroism, greater hardness.
Kyanite – Rarely transparent, lower hardness, and lacks purplish tinge.
Tanzanite – Has a greater refractive index and specific gravity.
Amethyst – Has a deeper purple color.
Jade is best known as a green ornamental stone. Its colors varies from light to dark green, but it may also be other colors such as white, gray, and purple. Jade is actually the gemstone name for two different mineral forms, Jadeite and Nephrite. These two minerals can be identical in appearance and are similar in their physical properties, and until modern times no distinction was made between the two different types of Jade. While Nephrite is generally only green, cream, or white, Jadeite colors can range through the color spectrum with more exotic colors.