Chemical garden Chemical garden A chemical garden is an experiment in chemistry usually performed by adding metal salts such as copper sulfate or cobalt(II) chloride to an aqueous solution of sodium silicate (otherwise known as waterglass). This results in growth of plant-like forms in minutes to hours. The chemical garden was first observed and described by Johann Rudolf Glauber in 1646. In its original form, the chemical garden involved the introduction of ferrous chloride (FeCl) crystals into a solution of potassium silicate (KSiO). The chemical garden relies on most transition metal silicates being insoluble in water and coloured. A metal salt such
Cobalt was predominantly used as a pigment. It has been used since the Middle Ages to make smalt, a blue-colored glass. Smalt is produced by melting a mixture of roasted mineral smaltite, quartz and potassium carbonate, which yields a dark blue silicate glass, which is finely ground after the production. Smalt was widely used to color glass and as pigment for paintings. In 1780, Sven Rinman discovered cobalt green, and in 1802 Louis Jacques Thénard discovered cobalt blue. Cobalt pigments such as cobalt blue (cobalt aluminate), cerulean blue (cobalt(II) stannate), various hues of cobalt green (a mixture of cobalt(II) oxide and