Urostealith is a fatty

Lipid

Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...

 or resinous

Rosin

.Rosin, also called colophony or Greek pitch , is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black...

 substance identified by the Austrian chemist

Chemistry

Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

 J. F. Heller

Johann Florian Heller

Johann Florian Heller was an Austrian chemist who was one of the founders of clinical chemistry.Heller was born in Vienna, Austria. He studied chemistry in Prague and later with Liebig and Wöhler at Giessen...

 in 1845 as the main constituent of some bladder stones.

According to Heller's and other contemporay descriptions, urostealith is a soft brown substance, insoluble in water, sparingly soluble in alcohol

Ethanol

Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...

 and easily soluble in ether

Diethyl ether

Diethyl ether, also known as ethyl ether, simply ether, or ethoxyethane, is an organic compound in the ether class with the formula . It is a colorless, highly volatile flammable liquid with a characteristic odor...

. Upon heating it softens at first, then expands and carbonizes before melting. It dissolves in solutions of sodium carbonate

Sodium carbonate

Sodium carbonate , Na2CO3 is a sodium salt of carbonic acid. It most commonly occurs as a crystalline heptahydrate, which readily effloresces to form a white powder, the monohydrate. Sodium carbonate is domestically well-known for its everyday use as a water softener. It can be extracted from the...

, and the latter was successfully used by Heller to dissolve and break up stones in a patient's bladder.

Urostealith stones seem to be very rare. The circumstances that lead to their formation, as well as the composition of the substance, are still obscure, and little has been published on the topic.