What Are Crystals?

SMOKY QUARTZ

Crystals are solid material in which the atoms are arranged in regular geometrical patterns. The crystal shape is the external expression of the mineral's regular internal atomic structure. Temperature, pressure, chemical conditions and the amount of space available are some of the things that affect their growth. Many crystallise from watery solutions, some from molten rock as during volcanic eruptions when lava cools rapidly.

Each mineral will always form in a range of crystal shapes. Although there are literally thousands of minerals, their crystal shape can be grouped on the basis of their symmetry into seven systems of three dimensional patterns.

CUBIC

Four 3-Fold Axes

TETRAGONAL

HEXAGONAL

TRIGONAL

One 4-Fold Axis

One 6-Fold Axis

One 3-Fold Axis

ORTHORHOMBIC

MONOCLINIC

TRICLINIC

Three 2-Fold Axes

One 2-Fold Axis

No Axes