1st - Gold 
January 
February 
March 
April 
May 
June 
July 
August 
September 
October 
November 
December 
Capricorn - Garnet 
Aquarius - Amethyst 
Pisces - Aquamarine 
Aries - Diamond 
Taurus - Emerald 
Gemini - Pearl 
Cancer - Ruby 
Leo - Peridot 
Virgo - Blue Sapphire 
Libra - Opal 
Scorpio - Topaz 
Sagittarius - Tanzanite 
Tanzanite vs Iolite
Which Best Blue Gemstone Should You Choose?
Choosing the right blue gemstone can be challenging. Tanzanite and Iolite are two striking options that differ in colour intensity, clarity, hardness, and overall value.
This Tanzanite vs Iolite comparison guide will help you understand the differences and determine which gemstone is best for your jewellery collection.
Tanzanite vs Iolite: Quick Comparison
| Feature | Tanzanite | Iolite |
|---|---|---|
| Mineral Family | Zoisite | Cordierite |
| Hardness | 6.5 – 7 – Moderate durability | 7 – Moderate durability |
| Value | High; rare and collectible | Moderate; affordable blue gemstone |
| Best For | High-end jewellery, statement pieces | Everyday jewellery, earrings, pendants |
| Professional Guides | Tanzanite Buyer’s Guide | Iolite Buyer’s Guide |
Tanzanite Features, Colour & Investment Value Explained
Tanzanite is renowned for its vivid blue-violet colour and exceptional brilliance. Its colour intensity and clarity directly influence value, with deep blue stones being the most sought-after.
Origins & History:
Tanzanite is found exclusively in northern Tanzania. Discovered in the 1960s, it quickly gained popularity as a rare, collectible gemstone.
Price Guide (per carat):
R3,500 – R80,000 depending on quality and size.
Iolite Features, Colour & Durability Explained
Iolite is an attractive blue-violet gemstone, often slightly paler than tanzanite. Its moderate hardness (Mohs 7) makes it suitable for earrings, pendants, and other jewellery that avoids heavy daily wear.
Origins & History:
Iolite is mined in India, Sri Lanka, Brazil, and Madagascar. Historically known as “water sapphire” due to its pleochroism, iolite displays different colours from different angles.
Price Guide (per carat):
R500 – R5,000 depending on quality.
Tanzanite vs Iolite: Detailed Technical Comparison
| Feature | Tanzanite | Iolite |
|---|---|---|
| Chemical Composition | Calcium aluminium silicate (Ca2Al3(SiO4)3(OH)) | Magnesium aluminium silicate (Mg2Al4Si5O18) |
| Colour | Blue-violet, deep indigo, rich cornflower blue | Blue-violet, pale blue, greyish-blue |
| Hardness (Mohs) | 6.5 – 7 – moderate durability | 7 – moderate durability |
| Refractive Index | 1.691 – 1.700 | 1.542 – 1.551 |
| Specific Gravity | 3.35 | 2.58 – 2.66 |
| Clarity & Inclusions | Generally eye-clean; minor inclusions acceptable | Typically eye-clean; pleochroic colour shifts visible |
| Origin | Northern Tanzania | India, Sri Lanka, Brazil, Madagascar |
| Treatment | Heat treatment common to enhance colour | Mostly untreated; rare enhancements |
| Best Use | Statement rings, high-end jewellery | Everyday jewellery, earrings, pendants |
Tanzanite vs Iolite: Colour, Hardness & Care Tips
Colour Comparison:
- Tanzanite: Rich blue-violet; deeper tones are more valuable.
- Iolite: Blue-violet with natural pleochroism; colour shifts depending on viewing angle.
Hardness & Durability:
- Tanzanite: Mohs 6.5–7; suitable for occasional wear or protective settings.
- Iolite: Mohs 7; durable for pendants and earrings but avoid rough daily use.
Care Tips:
- Tanzanite: Avoid sharp impacts and heat; clean with mild soap and water.
- Iolite: Avoid prolonged sun exposure and harsh chemicals; gentle cleaning recommended.
Tanzanite vs Iolite: How to Tell Them Apart
💡 Tip: Look for pleochroism in Iolite (colour changes with angle). Tanzanite shows a more uniform blue-violet hue. Professional verification recommended for high-value stones.
Tanzanite Summary
- Hardness: Mohs 6.5 – 7
- Colour: Deep blue-violet, cornflower blue
- Refractive Index: 1.691 – 1.700
- Inclusions: Minor, generally eye-clean
- Care: Avoid rough wear; clean gently
Iolite Summary
- Hardness: Mohs 7
- Colour: Blue-violet, pleochroic shifts visible
- Refractive Index: 1.542 – 1.551
- Inclusions: Minimal; usually eye-clean
- Care: Suitable for pendants/earrings; gentle cleaning
Buying Tips
- Request certification for Tanzanite.
- Examine pleochroism when buying Iolite.
- Consider treatment disclosures; Tanzanite is commonly heat-treated.
- Select protective settings for Tanzanite rings; Iolite is more durable in pendants/earrings.
- Browse our Tanzanite Gemstones and Iolite Gemstones.
Which Blue Gemstone Should You Choose?
Both gemstones are stunning; choice depends on personal preference, durability, and budget.
Tanzanite: Ideal for collectors, statement jewellery, and rare gemstones.
Iolite: Affordable, durable, and attractive blue gemstone for everyday jewellery.
Tanzanite vs Iolite FAQ’s
Can Iolite be mistaken for Tanzanite?
Yes, due to similar blue-violet hues; check pleochroism.
Are Tanzanite gemstones expensive?
Yes, especially deep blue stones and larger sizes.
Can Iolite be worn daily?
Yes, but avoid rough impact; best for pendants/earrings.
Do Tanzanites require special care?
Yes, avoid impact and harsh chemicals; Mohs 6.5–7 means moderate durability.
Are Tanzanite stones treated?
Most are heat-treated to enhance colour.
Which is better for investment: Tanzanite or Iolite?
Tanzanite, due to rarity and collector demand.
COMPARE GEMSTONES WITH CONFIDENCE
Gemstone Comparison Guides
Choosing between two beautiful gemstones can be challenging. Our professional Gemstone Comparison Guides help you clearly understand the differences between popular gemstones so you can make a confident and informed choice.
Each comparison explores the key factors that influence gemstone quality and value, including colour, clarity, durability, rarity and typical treatments. You will also learn how similar-looking gemstones differ in appearance, composition, hardness and more.
HERE IS ALL THE PROFESSIONAL INFORMATION YOU NEED
Gemstone Buyer's Guides
Buying a gemstone should be exciting — but understanding quality, rarity and value is essential before making the right choice. Our professional Gemstone Buyer’s Guides help you understand how colour, clarity, cut and treatments influence the beauty and value of different gemstones.
Each guide explains the key quality factors used by gemologists, including gemstone composition, colour grading, natural inclusions, treatments and origin. You will also learn how these factors affect rarity, durability and market value.
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