A group of natural inorganic pigments whose green color comes from divalent iron metasilicate. These substances have been used since ancient times and, depending on their place of origin, contain oxides of iron, aluminum, silicon, potassium, manganese and calcium in different proportions. One of the best sorts of green earths is Bohemian green earth, also known as glauconite, which ceased to be available after 1952 as a result of the Second World War but started being supplied again in small quantities a few years ago.
- Green Earths
01/30/2014 MarketSmart 2014