A proportion used in determining the dimensional relationship of a representation to that which it represents: a world map with a scale of 1:4,560,000. b. A calibrated line, as on a map or an architectural plan, indicating such a proportion.
Yttria (yttrium oxide, Y 2 O 3), was discovered by Johann Gadolin in 1794 in a mineral called gadolinite from Ytterby. Ytterby is the site of a quarry in Sweden which contains many unusual minerals containing erbium, terbium, and ytterbium as well as yttrium.
Yttrium is one of the rare elements, and can be found in houses in equipment such as colour televisions, fluorescent lamps, energy-saving lamps and glasses. Yttrium can rarely be found in nature, as it occurs in very small amounts. Yttrium is usually found only in two different kinds of ores.