Hardness of Minerals In the category gold discovery more articles and learn more information about Hardness of Minerals Reviews Price Specifications Features Image manuals videos Accessories All this in metal detectors for gold.
In terms of reliability, hardness is one of the better physical properties for
minerals. Specimens of the same mineral may vary slightly from one to
another, but generally they are quite consistent. Inconsistencies occur when
the specimen is impure, poorly crystallized, or actually an aggregate and not
an individual crystal.
Hardness is one measure of the strength of the structure of the mineral
relative to the strength of its chemical bonds. Minerals with small atoms,
packed tightly together with strong covalent bonds throughout tend to be the
hardest minerals. The softest minerals have metallic bonds or even weaker
van der Waals bonds as important components of their structure. Hardness is
generally consistent because the chemistry of minerals is generally consistent.
Hardness can be tested through scratching. A scratch on a mineral is actually
a groove produced by microfractures on the surface of the mineral. A mineral
can only be scratched by a harder substance. A hard mineral can scratch a
softer mineral, but a soft mineral can not scratch a harder mineral (no matter
how hard you try). Therefore, a relative scale can be established to account
for the differences in hardness simply by seeing which mineral scratches
another. That is exactly what French mineralogist Friedrich Mohs proposed
almost one hundred and seventy years ago. The Mohs Hardness Scale starting
with Talc at 1 and ending with Diamond at 10, is universally used around the
world as a way of distinguishing minerals. Simply put; the higher the number, the
harder the mineral.