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Wednesday, October 22, 2014

Question

What is the difference between marble and granite and what was the technique to identify them?


Answer

Marble is a metamorphic rock based on limestone while granite is volcanic in origin. Granite is much harder than marble, but both can be polished to a high gloss.
The simplest test I can think of consists of putting a few drops of acid bowl cleaner (with hydrochloric (muriatic) acid) onto a piece of stone in an out-of-the-way place and watching for a reaction. Bubbles indicate marble (the limestone dissolves), and none show granite or another non-reactive stone.

Lynn E. Krafft, ICAN/ATEX Editor
lekrafft@juno.com