QUESTION

Stone Quality - Can you please tell me what grade COAST GREEN granite is? I have a one person telling me it's grade 3 and another that it's grade 6!! I would really appreciate your help.

ANSWER

ANSWER - There is no such industry standard that grades granite with numbers like that.  Marble has a class A, B, C, D and that has nothing to do with granite.

Without checking, Coast Green doesn’t sound familiar, so it may be a marketing name. A certain geological type of stone doesn’t automatically have a certain classification because its physical properties can vary from source to source and from time to time. The stone supplied from a particular quarry in a particular area of the quarry needs to be tested to determine how its physical properties compare to minimum ASTM requirements.

It’s not easy getting this type of information, but the importer of the stone or the stone quarry should provide this to the consumer in order to substantiate it meets the minimum requirements and to determine its usage suitability and limitations. Good Luck!