vermiculite,we have both crude vermiculiteand exfoliated vermiculite in two types: one is Silver-grey type (Fe2O3 content around 5-8%, similar with South Africa vermiculite);the other type we call Golden-yellow type (Fe2O3 content around16-23%, similar products with India and Australia).The white typemainly used in refractories/insulations, the golden yellow typemainly used in agriculture and horticulture. If used foragriculture and horticulture, we suggest you use goldenvermiculite, because its PH is 6.5-7.2, for silver grayvermiculite,its PH is 8.5-9.5, that''s to say, compared with silververmiculite, golden vermiculite is more neutral. In Japan, Koreamarket, our customers choose golden vermiculite used foragriculture and horticulture .