Tanzanite Gemstones

What is tanzanite and what makes it distinctive?

Tanzanite is a blue-violet variety of the mineral zoisite, found in a single geological deposit near Merelani, Tanzania — making it geographically rarer than diamond. Its defining characteristic is strong trichroism: the stone shifts between violet, blue, and burgundy depending on the angle of light and the direction from which it is viewed. This optical property means no two tanzanite stones look identical under different lighting conditions. The most valued specimens sit in the vivid blue-violet range, sometimes described in trade shorthand as 'AAA' grade, though grading nomenclature varies between suppliers. Tanzanite owes its colour to trace amounts of vanadium within the zoisite crystal structure, activated by heat treatment — a process applied to virtually all commercial tanzanite to suppress the brownish tones present in rough material and bring out the characteristic blue-violet hue.

How to choose a tanzanite for setting into a ring

When selecting a tanzanite for setting into a ring, the three most important considerations are colour depth, clarity, and cut quality. Tanzanite responds well to oval and cushion cuts, which preserve carat weight from the rough while maximising the stone's colour saturation through their deeper pavilions. Round brilliant cuts are available but sacrifice more rough material. For a solitaire ring, a stone of at least 1.0ct will carry the colour effectively; smaller tanzanites under 0.5ct can appear pale in comparison. Clarity matters because tanzanite is typically eye-clean at the higher grades — visible inclusions reduce both the transparency that lets the colour read through the stone and its long-term structural integrity. Metal choice has a significant bearing on appearance: platinum and white gold allow the blue-violet tones to read without interference, while yellow gold warms the stone toward its violet register. Rose gold creates a strong contrast that some find arresting, though it shifts the perceived colour slightly.

Is tanzanite durable enough for everyday wear?

Tanzanite has a Mohs hardness of 6.5, which places it below sapphire (9), ruby (9), and even aquamarine (7.5–8). This means tanzanite is not ideally suited to a ring worn daily without care, particularly in exposed settings such as a high prong solitaire on a dominant hand. For occasional or dress-ring wear, tanzanite is entirely appropriate; for a daily-wear engagement ring, a bezel or half-bezel setting offers significantly more protection to the girdle and table than a standard four- or six-claw arrangement. Tanzanite should be cleaned with warm water and a soft brush only — ultrasonic and steam cleaners carry a real risk of thermal shock and should be avoided. Stored separately from harder stones, tanzanite will retain its polish for many years with moderate care.

What does tanzanite cost in the UK?

Tanzanite pricing is driven primarily by colour intensity, carat weight, and clarity grade. Pale or lightly saturated stones are considerably more accessible per carat than deeply saturated vivid blue-violet specimens of the same size. Because the Merelani deposit is finite and mining output fluctuates, tanzanite has seen periods of significant price appreciation — particularly for stones above 2.0ct, where deep colour is proportionally rarer. For context, Bridebook's 2026 UK average engagement ring spend sits at £2,247, and a well-specified tanzanite centre stone can fall either side of that figure depending on size and grade. When set into one of our rings, the total cost will include metalwork and setting labour. Loose tanzanite stones may be purchased individually with complimentary insured UK delivery and returned within 30 days, no questions asked, with no exclusions.

How long does it take to have a tanzanite set into a ring?

Purchasing a tanzanite loose gives full control over the setting design. Once a stone is selected, the ring process begins with a consultation and CAD design, followed by a silver or wax sample for try-on at our Hatton Garden workshop by appointment. From order confirmation, lead time is 7–14 working days depending on setting complexity — a simple bezel solitaire sits toward the shorter end, while an intricate pavé or split-shank design takes longer. The finished ring is cast, set by hand, polished, and hallmarked at the London Assay Office before insured UK delivery. Given tanzanite's moderate hardness, our setters take particular care during the setting stage to avoid pressure fractures at the girdle.