What tanzanite is
Tanzanite is a blue-violet variety of the mineral zoisite, found almost exclusively in one small region of Tanzania. Its colour ranges from lavender to deep violet-blue and can appear different in incandescent versus daylight. It is a genuine gemstone but distinct from a diamond in every physical property.
Hardness and durability differences
Diamonds rate 10 on the Mohs scale. Tanzanite sits at around 6.5 to 7 and is also brittle with cleavage planes, meaning it can chip or crack under impact. In a ring worn daily, this matters. Bezel or halo settings protect the tanzanite better than exposed claw prongs. A ring designed for occasional wear faces less risk.
How diamonds and tanzanite work together visually
Diamonds in a halo or channel around a tanzanite centre add brightness that complements the deep blue-violet saturation. The contrast in tone and brilliance is the appeal of the pairing. Quality of the diamond accent stones affects how the overall ring reads, so do not overlook the cut and colour of the surrounding stones.
Certification and value
Tanzanite is generally assessed by colour saturation, clarity, and carat weight. It is not graded by a standardised lab system comparable to GIA diamond grades, though some labs provide reports. For the diamond elements of a combined ring, request a certificate. Prodiam at The Paragon, Bedfordview, handles certified natural diamonds. Call +27 74 702 1976 or email the Prodiam team.
Decision table
Use the details, not a shortcut.
| Property | Diamond | Tanzanite |
|---|---|---|
| Mohs hardness | 10 | 6.5-7 |
| Durability | Very high | Moderate, brittle |
| Colour | Colourless to fancy | Violet-blue, trichroic |
| Certification | GIA, AGS, IGI widely used | No universal grading standard |
| Daily wear suitability | High | Moderate, protective setting recommended |
Direct answers
Common questions
Is tanzanite rarer than diamond?
Tanzanite comes from one very small area and supply is finite, but rarity alone does not determine market value or resale liquidity. Diamonds have a much more established global trade market.
Can tanzanite be cleaned with an ultrasonic cleaner?
No. Tanzanite can crack in ultrasonic cleaners. Use warm soapy water and a soft brush. Remove the ring before impact activities.
Will the tanzanite affect the value of a diamond ring?
The diamond and tanzanite components hold different resale markets. A certified diamond within the ring retains tradeable value separately from the coloured stone.
What setting is best for a tanzanite centre stone?
A full bezel or a halo setting with surrounding diamonds offers the most protection. Avoid high claw settings on a stone worn every day.
Where can I buy tanzanite and diamond rings in South Africa?
Jewellers across South Africa stock these combinations. For the diamond component assessed or certified, contact Prodiam in Bedfordview at the Prodiam team.