But here again, its low hardness (2.5-4) and perfect dodecahedral cleavage preclude sphalerite's wide use in jewelry.

With lower hardness comes lower specific gravity (2.60-2.90) and greater porosity: These properties are dependent on grain size.

Despite its low hardness relative to other gems, turquoise takes a good polish.

A procedure for waters of low hardness, i.e., less than 10 mg/1., is given in B.S.2690: Part 4: 1967.

The weak chemical bonding in its structure gives the mineral a low hardness around 1.5 and weak forms.

This process mechanically weakens the rods because the hydrides have lower hardness and ductility than metal.

It inhabits clear oligotrophic waters with low hardness.

It was only of local significance, because it had low hardness.

On the contrary, if the products require fine and precision pattern reproduction, it should be made of silicone with low hardness.

This explains the low hardness and high ductility of single crystals of copper.