shale rock on nature background.

alteration aphanitic argillaceous background basait black calcium calcsilicate carbon clay coal common composition diopside environment environmental existing felsic fluorite foliated fossil fuel gem gemmology gemology geological geology glassy gneiss granite green igneous isolated macro metasomatic mineral minerals most natural nature ore piece porphyritic produced raw rhyolite rock rocks rough sand science sedimentary shale shooting silicarich silicate single solid specimen spinach stone structure such tectonics texture tuff volcanic volcano which white wollastonite