Calcium alginate is an water-insoluble, gelatinous, cream coloured substance that can be created through the addition of aqueous calcium chloride to aqueous sodium alginate. Adding artificial flavours and colours creates a more tasty edible slime. Calcium alginate is also used for entrapment of enzymes and forming artificial seeds in Plant tissue culture.

“Alginate” is usually the salts of alginic acid, but it can also refer to derivatives of alginic acid and alginic acid itself; in some publications the term “algin” is used instead of alginate. Alginate is present in the cell walls of brown algae, as the calcium, magnesium and sodium salts of alginic acid.