Identify My Rock Marble

You obviously don t want to crush your rock if you think it s valuable but that isn t necessary.

Identify my rock marble.

It is composed primarily of the mineral calcite caco 3 and usually contains other minerals such as clay minerals micas quartz pyrite iron oxides and graphite under the conditions of metamorphism the calcite in the limestone recrystallizes to form a rock that is. Authentic marble is a metaphoric rock formed by applying heat to limestone forming crystals of calcite a relatively soft mineral. Igneous rocks such as granite or lava are tough frozen melts with little texture or layering rocks like these contain mostly black white and or gray minerals. Marble is a metamorphic rock that forms when limestone is subjected to the heat and pressure of metamorphism.

Because of this the surface of marble shows scratches and wear. The visible crystals in marble give it a characteristic granular surface and appearance but there are other properties used to identify the rock. Sedimentary rocks such as limestone or shale are hardened sediment with sandy or clay like layers strata they are usually brown to gray in color and may have fossils and water or wind marks. You can conduct a streak test with a piece of unglazed porcelain the back of a porcelain tile is ideal.

When you crush a rock its powder isn t always the same color as the rock itself and this powder can help identify the minerals in the rock. Marble can be scratched with a metal blade.