Iolite
A variety of Cordierite
What is Iolite?
Iolite is a blue to violet silicate mineral found in igneous and metamorphic rocks. Generally, the material has little commercial use. Synthetic iolite is used for making ceramic parts used in catalytic converters. The clear variety is called iolite, and it's cut as a gem and used in the jewelry industry.
Uses & Applications
The most transparent and inclusion-free specimens of iolite are used in the gem industry, as this hard mineral can be cut into faceted gemstones for use in necklaces, rings, and other decorative jewelry in a similar way to Sapphire. While some of these gems are quite breathtaking, they may not be as popular because many samples are hard to cut well; the stone appears differently colored from different angles.
Healing Properties
Disorders of the liver are said to be healed by iolite, and the belief is that the stone diminishes sleep problems. Iolite may alleviate the symptoms of rheumatism and stomach acidity. Its supposed connection with the third eye chakra means it serves to magnify motivation and increase willpower. It's also said to aid the removal of harmful habits.
Optical Properties
- Refractive Index
- 1.542-1.578
- Birefringence
- 0.008-0.012
- Pleochroism
- Strong trichroism: colorless to yellowish, pale blue, violet-blue
- Optical Character
- Biaxial positive or negative
- Dispersion
- 0.017
Discover Values
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Iolite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Iolite Localities Map
See where Iolite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Associated Chakras
Quick Facts
Physical Properties
- Color
- Blue to blue–violet
- Hardness (Mohs)
- 7 - 7.5
- Density
- 2.58 - 2.66 g/cm³
- Streak
- White
- Luster
- Greasy, Vitreous
- Crystal System
- Orthorhombic
Chemical Properties
- Chemical Formula
- (Mg,Fe)2Al3(AlSi5O18)
- Elements
- Al, Fe, Mg, O, Si
Also Known As
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Iolite FAQs
How do I identify Iolite?
Iolite can be identified by its hardness of 7 - 7.5 on the Mohs scale, Blue to blue–violet color, Greasy, Vitreous luster, Orthorhombic crystal system. Look for these key characteristics when examining specimens.
What color is Iolite?
Iolite typically appears in Blue to blue–violet. Color can vary depending on impurities and formation conditions.
How hard is Iolite?
Iolite has a hardness of 7 - 7.5 on the Mohs scale. This makes it a relatively hard mineral suitable for jewelry.