Understanding Tanzanite Grading: The 4Cs Explained

Like diamonds, tanzanite is graded on four criteria: Colour, Clarity, Cut, and Carat weight. However, tanzanite’s unique trichroic properties make colour grading especially important — and complex.

Colour: The most prized tanzanites display a deep, saturated violet-blue. The Tanzanite Foundation grades colour from Exceptional (vivid blue-violet) through Moderate to Pale. Stones over 5 carats tend to show the deepest saturation.

Clarity: Eye-clean stones (no visible inclusions) are the standard for fine tanzanite. Unlike diamonds, tanzanite frequently occurs in high clarity grades.

Cut: A well-cut tanzanite maximises the blue-violet face-up colour and minimises the brownish axis. Our master cutters in Arusha achieve this through precise orientation of the rough crystal.

Carat: Tanzanite is available in a wide range of sizes. Investment-grade stones typically start at 2 carats, with exceptional pieces exceeding 20 carats.