[{"from": "human", "value": "Could you give me a brief overview of this molecule? [O][=Si][=O]"}, {"from": "gpt", "value": "The molecule is a natural compound of silicon and oxygen found mostly in sand, Silica has three main crystalline varieties: quartz, tridymite, and cristobalite. Fine particulate silica dust from quartz rock causes over a long-term progressive lung injury, silicosis. (NCI04)"}]