Answer to Question #228399 in General Chemistry for vhinz

Question

 Compare and contrast the 7 crystal system. 

Answer 1

The seven crystal systems are a method of classifying crystals according to their atomic lattice or structure. The atomic lattice is a three dimensional network of atoms that are arranged in a symmetrical pattern. The shape of the lattice determines not only which crystal system the stone belongs to, but all of its physical properties and appearance. In some crystal healing practices the axial symmetry of a crystal is believed to directly influence its metaphysical properties. For example crystals in the Cubic System are believed to be grounding, because the cube is a symbol of the element Earth.

There are seven crystal systems or groups, each of which has a distinct atomic lattice. Here we have outlined the basic atomic structure of the seven systems, along with some common examples of each system.

Cubic Systemcubic crystal system

Also known as the isometric system. All three axes are of equal length and intersect at right angles. Based on a square inner structure.

Crystal shapes include:

Cube (diamond, fluorite, pyrite)

Octahedron (diamond, fluorite, magnetite)

Rhombic dodecahedron (garnet, lapis lazuli rarely crystallises)

Icosi-tetrahedron (pyrite, sphalerite)

Hexacisochedron (pyrite).

Common Cubic Crystals:

Diamond

Fluorite

Garnet

Gold

Pyrite

Silver

Spinel

Tetragonal SystemTetragonal crystal system

Two axes are of equal length and are in the same plane, the main axis is either longer or shorter, and all three intersect at right angles.

Based on a rectangular inner structure.

Crystal shapes include:

Four-sided prisms and pyramids

Trapezohedrons

Eight-sided and double pyramids

Icosi-tetrahedron (pyrite, sphalerite)

Hexacisochedron (pyrite