Rocks & Minerals

[Jessica]

A mineral is a naturally occurring, inorganic solid with a specific chemical composition and a specific regular arrangement of atoms.

Silica Tetrahedra (SiO[sub]4[/sub]) is the "building block" of most rocks and minerals. It defines the crystal shape, properties, and appearance of the different silicate minerals.

It can have different long range order of the tetrahedra in combination with each other or other atoms

• single (isolated): "olivine" (no shared oxygen atoms)
• chain structure: "pyroxene" (2 shared oxygen atoms)
• double chain structure: "asbestos" (2 shared oxygen atoms)
• sheet structure: "mica" (3 shared oxygen atoms)
• framework structure: "quartz" (all 4 shared oxygen atoms)

All minerals are built from regular, repeating arrangements of atoms.

A piece of wood is a solid, but it has no regular arrangement of atoms, so it is not a crystalline solid.


Mineral categories:

Native elements: gold, copper, diamond (C), sulfur

Oxides/Hydroxides: Fe[sub]2[/sub]O[sub]3[/sub], Al[sub]2[/sub]O[sub]3[/sub], H[sub]2[/sub]O

Halides: NaCl, KCl, CaF[sub]2[/sub]

Sulfides: PbS, ZnS, FeS[sub]2[/sub]

Sulfates: CaSO[sub]4[/sub], BaSO[sub]4[/sub]

Carbonates: CaCO[sub]3[/sub] (limestone), FeCO[sub]3[/sub], (Ca,Mg)(CO[sub]3[/sub])[sub]2[/sub]

Phosphates: Ca[sub]5[/sub](PO[sub]4[/sub])[sub]3[/sub](OH,Cl,F)