Marble is a metamorphic rock that forms when limestone is subjected to the heat and pressure of metamorphism.
Marble on microscope.
If the marble is completely smooth it was machine made and has no pontil marks.
Some common rock types as seen under the microscope.
Lines like this as well as smooth indents or bubbles do not indicate pontil marks found on handmade marbles.
Marble width 2 8 cm uk virtual microscope the united kingdom virtual microscope ukvm collection consists of igneous sedimentary and metamorphic rocks from around the uk.
Check for smooth lines or a single straight line that runs deep into the marble.
Rocks under the microscope.