The highest grade/quality of cubic zirconia is AAAAA (we write it as 5A), which measures 8.5 in hardness on the Mohs scale. White cubic zirconia stones are graded for quality. These resemble genuine diamonds. They are graded as A, AAA, and AAAAA, with AAAAA being the highest grade.
At Phroezn, we use only AAA (3A) or AAAAA (5A) Cubic Zirconia stones. The majority of our pieces are made with 5A Cubic Zirconia. We always ensure the quality of the stones used in any of our jewelry, is always included in the product description.