It occurs with native mercury, amalgam, cinnabar, mercurian tetrahedrite, eglestonite, terlinguaite, montroydite, kleinite, moschelite, kadyrelite, kuzminite, chursinite, kelyanite, calcite, limonite and various clay minerals.

[6] Calomel first entered Western medical literature in 1608, when Oswald Croll wrote about its preparation in his Tyroncium Chemicum.

It was not called calomel until 1655, when the name was created by Théodore de Mayerne,[7] who had published its preparation and formula in “Pharmacopoeia Londinensis" in 1618.

[6] By the 19th century, calomel was viewed as a panacea, or miracle drug, and was used against almost every disease, including syphilis, bronchitis, cholera, ingrown toenails, teething, gout, tuberculosis, influenza, and cancer.

[8] He noted that calomel had harmful effects causing gangrene on the skin, loss of teeth, and deterioration of the gums.

[8] Eventually calomel’s popularity began to wane as more research was done, and scientists discovered that the mercury in the compound was poisoning patients.

[13] Calomel is a powder that is white when pure, and it has been used as a pigment in painting in 17th century South Americas art and in European medieval manuscripts.

Once inhaled, the calomel enters the bloodstream and the mercury binds with the amino acids methionine, cysteine, homocysteine and taurine.

Mercury also has the ability to pass through the placenta, causing damage to unborn babies if a pregnant mother is taking calomel.

[11] The blue pill was an oral form of calomel containing mercury that was often mixed with a sweet substance, like licorice or sugar in order to be taken by mouth.

[11] Calomel was marketed as a purgative agent to relieve congestion and constipation; however, physicians at the time had no idea what the medication’s mechanism of action was.

[8] During the 19th century, calomel was used to treat numerous illnesses and diseases like mumps, typhoid fever, and others—especially those that impact the gastrointestinal tract, such as constipation, dysentery, and vomiting.

[9] As mercury softened the gums, calomel was the principal constituent of teething powders until the mid-twentieth century.

Calomel, in high doses, led to mercury poisoning, which had the potential to cause permanent deformities and even death.

It was also used by Charles Darwin to treat his mysterious chronic gastrointestinal illness, which has recently been attributed to Crohn's disease.