Once prized for their medicinal and talismanic properties, Goa stones, also known as Lapis de Goa, were a type of artificial bezoar invented in the mid-seventeenth century by one Gaspar Antonio, a lay Jesuit brother in the erstwhile Portuguese colony of Goa, India. They were used locally as well as exported to Europe until the late eighteenth century, and often stored or carried in specially made, ornate cases that reflected their value.

Bezoars are hard calciferous lumps that form in the digestive tracts of many mammals, including humans, as undigested material reacts with bile and gastric acid. A species of wild mountain goats found in and around present-day Iran — now known as bezoar ibex, Capra aegagrus aegagrus — were especially known for their bezoars, which were prized for their healing powers in medieval West Asia and Europe. Over time bezoars were used to treat a variety of illnesses, but they were primarily known as a remedy for poisoning — the word ‘bezoar’ originates from the Persian padzahr, meaning antidote. 

The earliest mention of the medicinal or talismanic use of bezoar stones is in medical treatises by ninth century Arab physicians Ibn-Sina and Ibn al-Beithar, who described the stones in terms of astrological magic, attributing their healing power partly to the celestial influence of the planet Jupiter. A century later this notion was discarded and theories of how the bezoar worked continued to develop, with some physicians arguing that the bezoar worked as an antidote by extracting poison through sympathetic attraction. From the twelfth century on, reports of the bezoar and its healing powers travelled from the Arab world to Europe, where it quickly became a popular remedy for a host of ailments from poisoning and plague to depression and fevers. In Goa, one sixteenth century pharmaceutical treatise published by a Portuguese physician discusses the medicinal use of bezoar stones extensively.

Between the twelfth and the seventeenth centuries, the widespread use of bezoars in Europe led to them being increasingly extracted across the world, from various animals, such as monkeys, oxen and antelopes. A French travelogue from the seventeenth century records the harvesting of bezoars from goats in the Deccan region of India. With increased trade between Europe, Asia and the Americas in the sixteenth and seventeenth centuries, bezoars became desirable not only as medicinal objects but also as fashionable collector’s items. By the seventeenth century natural bezoars had become difficult to source and extremely expensive, valued at several times their weight in gold. Counterfeit bezoars, often made with poisonous ingredients, appeared in the market — the now-commonplace legal disclaimer ‘Buyer beware’ was in fact first heard in a legal dispute over a fake bezoar. One of the few safe and effective substitutes for natural bezoars was the Goa stone.

Portuguese Jesuits arrived in Goa in 1542 as part of a larger wave of Portuguese missionaries and explorers; in addition to their activities and contributions to crafts, education, trade and other fields, they studied and recorded indigenous medicinal practices. They established apothecaries to serve the local population; these eventually became important centres for global pharmaceutical exchange and the creation of new formulations and remedies. The Goa stone was one such innovation. Antonio’s recipe was kept a closely guarded secret; after his death, it passed onto the priest Father Jorge Ungarate and the Jesuits continued producing the stones until their expulsion from Goa in 1749. The recipe then passed on to the Capuchin Franciscan monks in Goa who produced the stones in the Convento da Madre de Deus until the convent was shut down in the early nineteenth century. Production then shifted to the Convento do Sao Francisco until the mid-nineteenth century, although by then the demand for the stones and belief in their efficacy had drastically reduced because of the rise of modern medicine.

Through the eighteenth century Goa stones were traded across Europe and other cities across the world where Jesuit colleges had been established, such as Macao in China. Imitation Goa stones also appeared in the market; they were much cheaper than the originals, but the Jesuits retained their monopoly through a rigorous certification process that assured the buyer of the authenticity of their purchase. 

The stone was made from a small quantity of natural bezoar blended into a paste along with various other substances meant to enhance its healing properties. This mixture was shaped into a ball, rolled onto gold leaf, and polished with cloth when dry. Antonio’s original recipe and its variations listed ingredients such crushed crab claws, oyster shells, fossil shark teeth, ambergris (a secretion of sperm whales), terra sigillata (a type of clay from Greece), deer horn, narwhal tusk, and precious stones and metals including rubies, emeralds, sapphire, jacinth, gold and silver. Later versions of the recipe omitted precious gems in the interest of affordability. 

The stones are smooth and typically dark grey or green in colour with gold streaks. They vary in shape — some are ovoid or hemispherical, others are in the form of cylindrical sticks or quadrangular prisms. The larger, round Goa stones are about 5 to 7 centimetres in diameter and weigh around 300 grams. Smaller ones were often used in rings, pendants and brooches as talismans.

The most common way to ingest a dose of bezoar stone was by mixing shavings from the stone into beverages such as tea, wine and water. Bezoars were often prescribed as cordials or tonics. They also worked to relieve fevers by causing excessive sweating. Goa stones are reported to have had a neutral, slightly sweet and earthy taste.

Members of royalty and nobility had natural bezoars or Goa stones set in jewellery so that they would have an antidote ready at hand in the event of poisoning; Queen Elizabeth I of England is reported to have worn a Goa stone set in a ring. The stones were also thought to protect the wearer from the plague. Those who could not afford to purchase whole stones would rent them or purchase small shavings.

Wealthy buyers of Goa stones stored them in ornate cases, typically gold, which was thought to amplify their healing power. Such cases appear in records of European treasuries and collections of curios from the seventeenth century onward. Most are spherical or ovoid, usually between 3 and 7 centimetres in diameter, constructed in two halves so that the top can be lifted off to place or remove the stone. They often feature a metal cage decorated with some form of openwork riveted to a smooth metal surface below. Two such cases, one gold and the other silver, housed at the Metropolitan Museum of Art, New York also have stands featuring three double scroll legs. The gold case, probably made in Goa in the late seventeenth or early eighteenth century, is larger than average and especially ornate. The dense and intricate latticework in solid gold features foliage in arabesque patterns as well as monkeys, foxes, gazelles, hares and European mythological beasts such as unicorns and griffins. The case is topped with a gold finial in the form of a bird. The design, materials and craftsmanship of this case, including the tripod stand, is an expression of the object’s position in the networks of global trade in the seventeenth century, combining West Asian, Iberian, Indian, and European stylistic elements.

The silver case at the Metropolitan Museum — similar to several others in museums and private collections — is less elaborate and slightly smaller. Also thought to have been made in India, the ovoid cage of mercury-gilded silver openwork in arabesque patterns is attached to a smooth base layer of gilded silver. A similarly carved specimen housed at the Science Museum, London, has a chain and clip attached to the round cage, presumably to carry the stone around. Other cases for carrying Goa stones could be much more spare, such as a mount featuring four minimally decorated brass bands that wrap around the stone, with a loop for a chain, likely made in Goa in the seventeenth or eighteenth century. One case that belonged to the sixteenth-century Duke of Alba, now housed at the Kunsthistorisches Museum in Vienna, is in the form of a horizontal cylindrical pendant that hangs from three short gold chains; the Duke’s coat of arms is engraved onto the pendant’s gold lattice cage. 

The British Museum and the Wellcome Collection in London also house specimens of Goa stones and their cases.