silica- William Henry Harrison (Wikipedia)
William Henry Harrison (February 9, 1773 – April 4, 1841) was an American military officer and politician who served as the ninth president of the United States from March 4 to April 4, 1841, the shortest presidency in U.S. history. He was also the first U.S. president to die in office, causing a brief constitutional crisis since presidential succession was not then fully defined in the U.S. Constitution. Harrison was the last president born as a British subject in the Thirteen Colonies and was the grandfather of Benjamin Harrison, the 23rd U.S. president.
- Diatomaceous earth (Wikipedia)
Diatomaceous earth (/ˌdaɪ.ətəˈmeɪʃəs/ DY-ə-tə-MAY-shəs), also known as diatomite (/daɪˈætəmaɪt/ dy-AT-ə-myte), celite, or kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 mm to less than 1 μm, but typically 10 to 200 μm. Depending on the granularity, this powder can have an abrasive feel, similar to pumice powder, and has a low density as a result of its high porosity. The typical chemical composition of oven-dried diatomaceous earth is 80–90% silica, with 2–4% alumina (attributed mostly to clay minerals), and 0.5–2% iron oxide.