7
A triclinic crystal system has three unequal crystallographic axes that intersect at oblique angles.
12
Corundum is in the trigonal crystal system.
hexagonal crystal system ( 6 sided )
Fluorite belongs to the same crystal system as salt - the cubic (also known as the isometric) crystal system.
The crystal system of pyrite is isometric, also known as cubic.
monoclinic
There are 6 equivalent (111) planes in an orthorhombic crystal system. This is because in an orthorhombic crystal system, the axes are of different lengths and perpendicular to each other, creating 6 symmetrical orientations for the (111) planes.
plagioclase, microcline, rhodonite, turquoise, wollastonite, amblygonite, and many more.
symmetry
Yes, the mineral malachite does have a crystal structure.
it has a very tight crystalline structure and small but definite porosity