 Knowledge
Base |
Measurement of hardness |
The objective of the measurement of hardness (MOH) scale is to measure
stone resistance to hardness. When sediment and grit are harder than
the surface, they will scratch and harm the stone. 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.
Listed below is the famous MOHS for stone. This is a guide developed
in the 1800's, which helps evaluate the strengths and weakness of
the stone being used. For example, softer stone would require less
active chemical and a more frequent dust-mopping program. |
| Hardness |
Type |
| 10 |
Diamond |
| 9 |
Corundum |
| 8 |
Topaze |
| 7 |
Quartz (Granite) |
| 6 |
Feldspar (Granite) |
| 5 |
Apatite |
| 4 |
Fluorite |
| 3 |
Calcite (Most marbles) |
| 2 |
Gypsum |
| 1 |
Talc |
|
| Marble is a relatively soft stone. On a measurement
of hardness scale, marble is approximately a three out of ten. Marble
is made of calcium, just like your teeth. If you eat something too
hard you will break your tooth. If you eat a lot of sugar you will
get a cavity. Stone reacts the same way. If an improper chemical is
applied to the surface, corrosion will begin to from cavities in the
stone. |
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