Two Beautiful Blues, Very Different Properties
Sapphire and tanzanite are both beloved blue gemstones, but they differ dramatically in hardness, rarity, price, and suitability for different types of jewelry. Understanding these differences helps you choose the right blue gemstone for your needs.
Sapphire
- Hardness: 9 on Mohs scale — the second hardest gemstone after diamond. Extremely durable for daily wear including rings
- Color: Blue is the classic sapphire color, but sapphires come in every color except red (red corundum is called ruby). Blue sapphire ranges from pale sky blue to deep royal blue to midnight blue
- Durability: Exceptional. Suitable for engagement rings and daily-wear jewelry. Will not scratch, chip, or deteriorate under normal conditions
- Price: Premium pricing for quality blue sapphires. Fine sapphires can cost as much or more than diamonds per carat
- Origin: Mined primarily in Sri Lanka, Myanmar, Kashmir, Madagascar, and Australia. Kashmir sapphires are the most valued
- Best for: Any jewelry application, including engagement rings and everyday wear. The hardness makes it suitable for everything
Tanzanite
- Hardness: 6-7 on Mohs scale — significantly softer than sapphire. More susceptible to scratching and chipping. Requires careful handling
- Color: A unique blue-violet that shifts between blue and purple depending on the viewing angle (pleochroism). This color-shifting quality is one of tanzanite's most distinctive features
- Durability: Moderate. Suitable for earrings, pendants, and occasional-wear rings. Not recommended for daily-wear rings due to hardness limitations
- Price: More affordable than sapphire for comparable visual quality. The price reflects both lower hardness and more limited demand
- Origin: Found in only one place on earth: the Merelani Hills near Mount Kilimanjaro, Tanzania. This single-source origin makes it geologically rare
- Best for: Earrings, pendants, and protected settings. Stunning in jewelry that does not receive heavy daily wear
Side by Side
- For engagement rings: Sapphire wins. The hardness difference is critical for a ring worn daily for decades
- For earrings: Both are excellent. Earrings receive minimal wear. Choose based on color preference
- For pendants: Both are excellent. Pendants are well-protected. Tanzanite's color-shifting quality is beautiful in a pendant
- For investment: Neither should be purchased as a financial investment. Buy for beauty
With Diamonds
Both gemstones pair beautifully with diamond accents. Diamond halos, diamond-set bands, and diamond side stones enhance both sapphire and tanzanite jewelry. Lab-grown diamonds make these combinations accessible at every budget.