| Limestone | ASTM C568/C568M, Standard Specification for Limestone Dimension Stone | Class I — Low Absorption | Not more than 0.75% | Lower moisture uptake than the higher limestone classes. The material may be more suitable for applications where reduced water penetration is important, subject to the complete project specification. | Consider for exterior or moisture-exposed applications when the tested lot meets the required durability, strength, freeze-thaw, and finish requirements. | Request an independent ASTM C97/C97M test report showing absorption, bulk specific gravity, and density for the supplied stone. |
| Limestone | ASTM C568/C568M, Standard Specification for Limestone Dimension Stone | Class II — Medium Absorption | More than 0.75% and not more than 3.0% | Moderate moisture uptake. Performance can vary considerably within this range, so the actual test value and intended exposure should be reviewed together. | Often evaluated for interior and selected exterior uses. Sealers, joint design, drainage, climate, and maintenance requirements should be assessed for the specific project. | Request the absorption result for the actual quarry source and production lot, together with strength and weathering test data where applicable. |
| Limestone | ASTM C568/C568M, Standard Specification for Limestone Dimension Stone | Class III — High Absorption | More than 3.0% and not more than 7.5% | Higher moisture uptake. The stone may require closer evaluation for staining, freeze-thaw exposure, moisture movement, detailing, and long-term maintenance. | Use only after confirming that the absorption level, climate, installation method, drainage, and intended service conditions are compatible. | Obtain current ASTM C97/C97M results and project-specific durability testing. Do not approve the material based on appearance alone. |
| Marble | ASTM C503/C503M, Standard Specification for Marble Dimension Stone | No Direct C568-Style Class I–III Scale | Use the applicable ASTM C503/C503M physical requirement and the project specification; do not automatically assign a C568 limestone class. | ASTM C503/C503M is a separate marble specification. Its acceptance requirements should be checked according to the specified marble type, application, and current standard edition. | Marble should be evaluated using the actual measured absorption, density, strength, finish, intended exposure, and potential sensitivity to staining or chemical attack. | Request an ASTM C97/C97M laboratory report, the applicable ASTM C503/C503M compliance statement, quarry and lot identification, and any project-required durability or stain-resistance testing. |