These concentric shaped specimens are from Quebec Canada.  They are composed of calcium carbonate and were formed in Quaternary deposits left in lakes by receding glaciers.

Each piece is approximately 2"+  And as you can see, each piece is totally unique. 

The Indian Story of the FAIRY STONE, Northern Quebec version.

The Indians call them ''FAIRY STONES'' for since hundreds of years.  They often carried them as lucky charms when they went on fishing or hunting expeditions.  Lovers offered the most beautiful ''FAIRY STONES'' to their loved ones.  The biggest specimens occupied a place of honor in their homes, or according to the legend, these special stones assured a protection against the bad spirits.  They also brought Good Health and Prosperity to the occupants of the premise.  One of the main rivers where to find fairy stones is the Harricana river, the second longest river in Canada so these '' fairy stones '' are at the origin of the name Harricana river.  In effects, when the first Indians came up the rivers towards Abitibi, a stop on these beaches made them realized the presence of these strange pebbles which for them; strangely look like ''biscuits''. This is the reason they named the river ''Harricana'' which means ''river of the biscuits'' in Algonquin language.

The originality and the forms of these stones are a phenomenon proper to Northern Quebec, Canada. They formed especially on the bottom of very big lakes with a glacier origin.  These stones are found in the soft deposits of the quaternary where they were found in the ponds having occupied the depression of the retreat of the big glacial front: subsequently they were carried by the water and deposited on the shores of some particular lakes and rivers.

The superior face of the concretion is usually smooth and regular as for the inferior face is often rough with puffed up spherics.  The irregular lines on certain stones are caused by the traces left by miniature worms or organic remains which were fossilized millions of years ago, as if earth wanted to keep them in the memory of its geological computer!