Tanzanite Carat Weight
WHAT IS CARAT WEIGHT?
This is a term we are all familiar with. Just like diamonds, tanzanites are weighed in carats. The higher the carats, the heavier the stone.
How do you measure tanzanite?
When you see “length × width × depth” measurements for a tanzanite, they are describing the stone’s exact size in millimeters, across three dimensions:
Example: A tanzanite listed as 8.0 × 6.0 × 4.0 mm means:
- 8.0 mm long (face-up, longest dimension)
- 6.0 mm wide (face-up, shortest dimension)
- 4.00 mm deep (from top to bottom)
Why it matters:
It is the stone's length and width, not carat weight, that tells you how big it will look when set. As each tanzanite is cut differently, the stone's depth also varies from one to another.
MEASURING SIZE FROM CARAT WEIGHT
If you place a one-carat diamond next to a one-carat tanzanite, they will not look the same in size. This is because diamonds are heavier than tanzanites.
In addition, the cutting styles used for diamonds are very different from those used for colored stones, and the proportions between the two tend to also be different as a result.
When evaluating a tanzanite’s size, you should view it from the top, because that is how it will be seen when set into a ring or jewelry item. To get the idea of the stone’s size, check its face-up measurements (length x width).