4.1 Petrographic examinations are made for the following purposes:
4.1.1 Determine the physical and chemical characteristics (mineralogy, texture, and composition) of the stone specimen that may be observed by petrographic methods and that have a bearing on the performance of the material in its intended use.
4.1.2 Describe and classify the minerals of the specimen.
4.1.3 Classify the stone both commercially and geologically based on Terminology C119, recognizing the differences in nomenclature; and based on the following standards, as appropriate:
Specification C406
Specification C503
Specification C568
Specification C615
Specification C616
Specification C629
Specification C1526
Specification C1527
4.1.4 Determine the relative amounts of the minerals of the specimen and constituents that have a bearing on the performance of the material in its intended use.
4.1.5 Compare characteristics of the stone with specimens from one or more sources, for which test data or performance records are available.
4.2 The petrographer should be told in as much detail as necessary, the purposes and objectives of the examination, the kind of information needed, and the extent of examination desired.
4.2.1 Pertinent background information, including results of prior testing, such as physical and mechanical testing, should be made available. The petrographer’s advice and judgment should be sought regarding the extent of the examination. Available physical and mechanical testing may include the following:
Test Methods C97
Test Method C99
Test Method C170
Test Method C880
Test Methods C120
Test Method C121
Test Method C241
Test Method C1353
Test Method C217
4.3 This guide may form the basis for establishing arrangements between a purchaser of consulting petrographic service and the petrographer. In such a case, the purchaser and the consultant should together determine the kind, extent, and objectives of the examination and analyses to be made, and should record their agreement in writing. The agreement may stipulate specific determinations to be made, observations to be reported, funds to be obligated, or a combination of these or other conditions.