These are mineral colors and they were developed for every hue on the color wheel. They replaced paints made from expensive semi-precious stones or highly toxic compounds. While Blue is abundant in the sky and water, it is scarce under ground. Until the beginning of the 18th Century the only blue oil colors were made from semi-precious stones, like lapis lazuli and azurite or a ground cobalt blue glass called smalt. Owning a painting with blue in it was a status symbol.
Cobalt blue is expensive even today for two reasons.
The price of raw cobalt ore is controlled by the government of Zaire, and the cost of processing the ore into pigment is high because it consumes tremendous amounts of natural gas. Indian Yellow became available in the middle of the 19th Century. Cows were force fed mango leaves and given no water. Indian Yellow was lost somewhere between the decline of cruelty to animals and the rise of manufactured pigments. Few green pigments are found naturally.