Among those famous individuals who received treatment using a bezoar is King Edward IV of England (1442-1483) who survived the effects of a poisoned wound, due solely to a bezoar in his possession. Likewise, Queen Elizabeth I of England (1533-1603) had a bezoar set in gold with unicorn's horn  given to her by her spy and magician John Dee.  However, the magic of the bezoar was not limited solely to the rich. Common folk could obtain bezoars from apothecaries who would lend them out at extortionate rates.
Another type of bezoar was the Trichinobezoar, which is made of hair – basically a huge hairball – and results in human individuals suffering from what is known as the Rapunzel Syndrome: the compulsive eating of one's own hair. Unlike the calcium bezoar, modern science has actually shown that the much more disgusting trichinobezoar could have been used successfully to remove arsenic from poisoned drinks during the middle ages, which is how it was most often used. Over time, bezoars faded out of use as more reliable forms of medical treatment came into existence. Today, the bezoar remains an interesting item in folklore and fantasy and references to them can be found in the works of Neil Gaiman (Sandman) and most notably J.K. Rowling (Harry Potter).
 Most likely the tusk of a narwhal.
 John Dee (1527-1608) is sometimes called Queen Elizabeth I's Merlin. He was a Welsh mathematician, scientist and occultist. He also practiced alchemy, divination and prescribed to Hermetic philosophy. He also worked as a spy for the crown going by the alias 007 -- a title made famous by Ian Fleming's fictional British spy James Bond.