Larimar Approximately 7.5mm Inner circumference approximately 16cm (size cannot be changed as it is a ready-made product). Re-strung loosely with white nylon elastic to prevent color transfer from the colored elastic. There are no black spots, but it is slightly greenish and the pattern is not clear. The stone has small scratches, dents, color unevenness, and chips near the stringing holes. Please refrain from purchasing if you are looking for perfection. 19696