Rocks on this page are not the thundereggs neither agates. I picked some rocks during my multiple trips to Oregon Coast, these rocks looked really different from others on the beach.   

Cut and polished Oregon Coast Rock. Size: 3'' x 2''

Cut and polished Oregon Coast Rock. Size: 3.25'' x 2.25''. Note small grey agate on top left corner.

Cut and polished Oregon Coast Rock. Size: 3.5'' x 2.75''

Cut and polished Oregon Coast Rock. Size: 3.5'' x 2''