Amalgam (chemistry) gold") would not be extractable from ore using hydro-mechanical methods. Large amounts of mercury were used in "placer mining", where deposits composed largely of decomposed granite slurry were separated in long runs of "riffle boxes", with mercury dumped in at the head of the run. The amalgam formed is a heavy solid mass of dull gray color. (The use of mercury in 19th century placer mining in California, now prohibited, has caused extensive pollution problems in riverine and estuarine environments, ongoing to this day.) Sometimes substantial slugs of amalgam are found in downstream river and creek bottoms by amateur wet-suited
Amalgam tattoo amalgam tattoos are managed by simple reassurance about the nature of the lesion. For example, if radio-opaque particles are demonstrated on the x-ray, biopsy is unnecessary. Amalgam tattoo is found in up to 1% of people in the general population. It is the most common cause of solitary or focal pigmentation of the oral mucosa. Amalgam tattoo Amalgam tattoo (also termed localized argyrosis, or focal argyrosis) is a grey, blue or black area of discoloration on the mucous membranes of the mouth, typically on the gums of the lower jaw. It is an iatrogenic lesion, caused by entry of dental