https://blog.gongquiz.com/2021/01/13/%ea%b4%91%eb%ac%bc-%ea%b2%b0%ec%a0%95-%eb%82%b4%ec%97%90-%eb%af%b8%ec%84%b8%ed%95%9c-%eb%b9%84%ec%a0%95%ec%a7%88-%ec%83%81%ed%83%9c%ec%9d%b8-%eb%a9%94%ed%83%80%eb%af%b9%ed%8a%b8metamict-%ed%98%84/