Moh''s Scale of Hardness | Marble Granite Supply of Illinois
Can barely be scratched with a knife blade. Its greatest use is as a source of phosphorus for common fertilizers. 6. Feldspar This mineral cannot be scratched by a knife blade but it can easily be scratched with window glass. It is found in most igneous rocks, and is an essential component of crystalline rocks such as granite, gabbro, and ...