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
Alchemy and chemistry in medieval Islam of alchemical texts: Theatrum Chemicum, and commented upon by Pseudo Aquinas in Aurora Consurgens. They both also give his (modified) image of the sage holding a chemical table (see image above). Al-Tughrai was an 11th–12th century Persian physician. whose work the"Masabih al-hikma wa-mafatih al-rahma" (The Lanterns of Wisdom and the Keys of Mercy) is one of the earliest works of material sciences. Al-Jildaki who was a Persian alchemist urged in his book the need for experimental chemistry and mentioned many experiments "Kanz al-ikhtisas fi ma'rifat al-khawas by Abu 'l-Qasim Aydamir al-Jildaki". Jābir analyzed each Aristotelian element in terms of Aristotle's