A crystal is a solid made-up of chemical elements. Chemical elements are composed of atoms and molecules. The atoms or molecules make-up all matter. .
The minerals in crystals all grow the same way. The particles of chemical elements have cohesion (attraction) to each other, which allows all the chemical particles to fit together. Atoms in minerals, which have patterns, are called crystalline. If there is no pattern to the crystal formation, then the substance is called non-crystalline, or amorphous.
Crystallography is the study of the outside form of crystals with its relation to chemistry and/or spatial arrangement. This study of the crystal state relates to many fields of employment; some include: biochemistry, engineering, metals, ceramics and synthetic gem production.
There are many different properties of minerals, which can be used to determine the identity of a mineral.
Some of the ways are:.
Cleavage- a minerals tendency to break along a smooth surface.
Fracture- the opposite of cleavage, a fracture is an uneven break.
Hardness- a minerals resistance to being scratched (determined by the "Mohs' Hardness .
Scale-) see Table 1.
Streak- the colour of the powder left behind when rubbed against a rough surface, harder .
than the mineral .
Colour- an aid to identifying a mineral but can also cause confusion.
Lustre- refers to the way minerals reflect light .
Some other properties and characteristics for identifying minerals are:.
Magnetism- when a mineral has a magnetic pull.
Odour- there are quite a few minerals with odours, but it is not usually strong unless the .
mineral has been struck, or freshly excavated.
Feel- minerals that have a distinctive feel are usually low in hardness, but not always.
Fluorescence- when ultraviolet light reacts with chemicals in a mineral and causes it to .
Taste- sometimes a very good characteristic and a key to identification .