It's called Stramatolite, its element is earth, and it's a receptive stone.

good for past-life meditation, relieving physical and emotional stress, ensures the flow of body fluids , massages the chakras." Another site says that it's good for improving vision, clearing the throat, use as a general tonic, physical well being, fortifying the aura, and that it strengthens teeth.

Stramatolites fall into 2 groups. organic creation and inorganic creation. The vast magority are organic which means fossil algae or some form of proto algae .it contains fossilized blue-algae which was the first known photosynthetic organism on Earth. But it is also believed that some of it may have been created through inorganic ways.

Metaphysically they are classified as fossils and have the properties of fossils.

If you follow the beliefs that the older the fossil the deeper and more primal the results of regression work then Stramatolites should be some of the best tools out there seeing many of them were created during a time which scientists now refer to when our oceans were a "primordial soup.