Aluminium foil decoration, and crafts, especially in bright metallic colours. Metallic aluminium, normally silvery in colour, can be made to take on other colours through anodisation. Anodising creates an oxide layer on the aluminium surface that can accept coloured dyes or metallic salts, depending on the process used. In this way, aluminium is used to create an inexpensive gold foil that actually contains no gold, and many other bright metallic colours. These foils are sometimes used in distinctive packaging. Foil is used by organic/petroleum geochemists for protecting rock samples taken from the fields and in the labs where the sample is subject
Foil (fencing) or fastening a knob on the point ("blossom", French "fleuret"). In addition to practising, some fencers took away the protection and used the sharp foil for duels. German students took up that practice in academic fencing and developed the "Pariser" ("Parisian") thrusting small sword for the "Stoßmensur" ("thrusting mensur"). The target area for modern foil is said to come from a time when fencing was practised with limited safety equipment. Another factor in the target area is that foil rules are derived from a period when dueling to the death was the norm. Hence, the favoured target area is the