Onyx is a form of chalcedony, (which also includes carnelian, agate, bloodstone), part of the quartz group. Like the other stones in the chalcedony family, onyx has a smooth, waxy luster. Onyx can be...
An ore is any material that helps support life on Earth.
Onyx is a banded variety of chalcedony, which is a cryptocrystalline form of silica.
iron ore is called haematite
Uranium ore is not...uranium ore !