We love to have a range of all shapes for each crystal type and here we have raw Black Obsidian also called roughs. The ones in the photo were 51g. You are being offered now 42g size.
Use it against psychic attack and to absorb negative energies from the environment. Black obsidian like these roughs draws out mental stress and tension. It stimulates growth on all levels, urging exploration of the unknown and opening new horizons. Read about properties of its Amorphous structure.
Black obsidian roughs are an inexpensive way to get large pieces at a cheap price so excellent for large grids.