The average typing speed is 38-40 words per minute (wpm) for adults  in a professional working environment (despite many incorrect  reports on the web that it is 50-60 wpm).
Chronic Health Effects The following chronic (long-term) health effects can occur at some time after exposure to Mica and can last for months or years: Cancer Hazard * Some Silicas have been shown to cause cancer in animals. The risk of cancer in humans from Mica is unclear at this time.
Mica has a metallic luster that adds to granite's ability to hold that just-polished look. It brings the sliver, black, brown, violet, and pink shades to granite. Feldspar. Feldspar is the second most common substance in granite. Feldspar is responsible for most of the colors you see in granite.