How to Identify Marble: What to Look For and Home Tests

Metamorphic rocks were changed by heat and pressure. Look for a sugary or platy texture, minerals lined up in one direction, and a hardness or ring that the parent rock did not have. The properties that identify Marble — color: Mostly white, but also black ('Fisk black' / 'French gray' / 'Champlain black'), red ('oriental'), and dark green ('verde antique'). For a rock, texture and grain size matter more than any single hardness number.

• [Limestone](/lookup/rocks-and-minerals/limestone): Marble forms from regional metamorphism and recrystallization of Cambrian-to-Ordovician limestone. Its mineral composition is similar (mostly calcite), but it is coarser-grained and denser.
• [Marble](/lookup/rocks-and-minerals/marble): The dark green stone sold commercially as 'verde antique marble' is not true marble at all — it is a metamorphosed ultramafic rock containing minerals like serpentine and talc.

The Shelburne Formation white marble deposit at Danby, Vermont, on the west limb of the Middlebury syncline.

Photograph a fresh, unweathered surface in daylight, then a second shot of any crystal faces or broken edge. Include a coin for scale. If you did a streak test, photograph the streak next to the specimen. The app suggests the likely mineral or rock; confirm with hardness and the tests above before you label it.

Marble's principal mineral is calcite (Mohs hardness about 3), but the overall hardness and specific gravity of the rock depend on how dense it is. No single citable value was found, so the field is left blank.