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Mineral
hardness is a physical characteristic that
can be tested, measured and compared to
other minerals. One method is to test the
hardness of one mineral against another.
This is done through the ability of a harder
material to scratch a softer one.
The
Mohs' Hardness Scale rates the hardness
of a mineral relative to others. It was
created by German mineralogist Friedrich
Mohs. The Mohs' Scale is one of several
definitions of hardness in materials science.
Mohs based his scale on ten readily available
minerals. The minerals are registered on
the scale by finding the hardest material
they can scratch. The Mohs' scale is relative,
not proportional.
The
table below compares Mohs' hardness to Absolute
hardness (as measured by a sclerometer).
The Mohs' scale is relative, meaning it
is a purely ordinal scale which lists the
minerals in order of hardness but does not
show differences of hardness between the
minerals as each mineral is only one unit
away from the next. This would indicate
that Quartz is only 7 times harder than
Talc and Diamond is only 10 times harder
than Talc.
The
Absolute hardness scale is proportional
showing a quantitative difference between
the minerals. This indicates that Quartz
is actually 100 times harder than Talc and
Diamond is actually 1500 times harder than
Talc.
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