Listed below is the famous Measurement of Hardness (MOH) Scale for stone. This is a guide developed in the 1800's which helps evaluate the strengths and weaknesses of the stone being used. For example, softer stones would require the use of a less active chemical and a more frequent dust mopping program.
Measurement Of Hardness Scale: 10 Diamond 9 Corundum 8 Topaz 7 Quartz (Granite) 6 Feldspar (Granite) 5 Apatite 4 Fluorite 3 Calcite (Most Marbles) 2 Gypsum 1 Talc The objective of the MOH Scale is to measure stones resistance to hardness.For example, a piece of hard plastic is about a 2.0. It will not scratch #3 Calcite (Marble). However, a piece of sand that measures a 6, will scratch #3 Calcite but will not scratch #7 Quartz which is Granite. The harder the stone, the more resistant it is to abrasion. Exterior sediment that is tracked in to buildings approximately measures from 3.0 to 7.0.