How to Grade a Mineral
Minerals are works of art, each mineral is totally unique and can be judged by a multitude of criteria. Some criteria are subjective (in the eye of the beholder), while others can be quite concrete. This grading system is a guide designed to help collectors assess how any given specimen ranks among its peers.
As a guide it provides reference points while still leaving open the possibility that a specimen can be beautiful and treasured simply due to the fact that you enjoy its appearance or that it moves you.
It is here that the worlds of art and nature meet.
How This Grading System Works
There are two sections to the guide: section A with five criteria, and section B with four criteria.
Each individual criteria is graded out of ten, ten being the best possible and most desirable score. Add up all nine criteria and then divide that sum by nine. This will give you an average score.
Of course there are some specimens where specific criteria are not applicable. In those cases, add up your individual criteria scores, then divide by the number of criteria used to get to your average score.
9-10 - Exceptional quality
8-8.9 - Very good quality
7-7.9 - Good quality
6.9 > - Not of collectible quality