Chemical garden

This experiment in chemistry is 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).

[5] In its original form, the chemical garden involved the introduction of ferrous chloride (FeCl2) crystals into a solution of potassium silicate (K2SiO3).

The usual upward direction of growth depends on the density of the fluid inside the semi-permeable membrane of the "plant" being lower than that of the surrounding waterglass solution.

For example, a green solution of trivalent chromium sulfate or chloride refuses to crystallize without slowly changing into the violet form[clarification needed], even if boiled until it concentrates into a tarry mass.

[3] For instance, this chemistry is related to the setting of Portland cement, the formation of hydrothermal vents, and during the corrosion of steel surfaces on which insoluble tubes can be formed.

The nature of the growth of the insoluble silicate tubes formed within chemical gardens is also useful in understanding classes of related behavior seen in fluids separated by membranes.

[11][12][13] According to researchers, "Chemical reactions like these have been studied for hundreds of years but they had not previously been shown to mimic these tiny iron-rich structures inside rocks.