Carrageenan carrageenan were estimated at $640 million. The largest producer of industrial carrageenan was the Philippines, where cultivated seaweed produces about 80% of the world supply, while China is the main exporter to global markets in the US and Europe. The most commonly used sources are "E. cottonii" ("Kappaphycus alvarezii", "K. striatum") and "E. spinosum" ("Eucheuma denticulatum"), which together provide about three-quarters of the world production. These grow from the sea surface to a depth of about 2 metres. The seaweed is normally grown on nylon lines strung between bamboo floats, and it is harvested after three months or so, when
Han purple and Han blue not a pigment). The purple color seen in samples of Han purple is created by the presence of red copper (I) oxide (CuO) which is formed when Han purple decomposes (the red and blue making purple). The decomposition of Han purple to form copper (I) oxide is Above 1050 °C, the CuO copper (II) oxide breaks down to copper (I) oxide: Both Han purple and Han blue are barium copper silicates (containing barium, copper, silicon, and oxygen). However, they differ in their formula, structure, and chemical properties. Han purple has the chemical formula BaCuSiO. Han purple has a layered structure