Stromatolite

This may resemble the micro crytalline quartz, Tiger's Eye, but in fact its a fossilzed bed of algae, known as Stromatolite.

A closer look of the specimen shows layers of different colours!

Stromatolites (from Greek στρώμα, strōma, mattress, bed, stratum, and λιθος, lithos, rock) are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria (commonly known as blue-green algae).