Basic Heraldry
There are five colours
Red - Blue - Green - Black - Purple
Each can be shown as lines across the field of the shield if no colouring available.

Two Metals
Gold - Silver
Gold, shown as Yellow of field of dots, whereas Silver is seen as a blank White field.

Two Furs

Ermine, which is the winter fur of the Stoat and Vair, being the fur of the Grey Squirrel.

Popular Shield shapes
1) UK
2) USA (e.g. Police)
3) Germany
4) France (Drago)
5) No particular region