set of various brown unpolished rocks with names

alunite background basalt bog bronzite brown calcite collage collection cut cutout description glendonite granite hematite ikaite iron isolated kidney limestone limonite magnetite mahogany mica mineral morion muscovite name natural normandite obsidian ore out pumice quartz rauchquarz raw rhyolite rock rough sample set smoky specimen sphene stone titanite travertin travertine unpolished various white