magnetite black

例句：

1. 1. The magnetite in the soil is a valuable resource for mining.
   土壤中的磁铁矿是采矿的重要资源。
2. 2. Ferruginous sandstones are often used as building materials.
   含铁砂岩常被用作建筑材料。
3. 3. The black color of this mineral attracts many people to explore its properties.
   这种矿物质的黑色吸引了许多人去探索其特性。