Horn corals

Do you have a touchstone? I have a bunch of them: objects that I like to take out and enjoy, or ponder or contemplate. Among them are the horn corals bequeathed to me by my great-aunt Lily, who early in the last century collected them from the shores of Skaneateles Lake in upstate New York. Aunt Lily lived a hundred years, but these fossils are three million times older. They have a proud place in the Fossil Pictures Gallery. If you have a good example to add, by all means let me know.

A touchstone isn't really a rock you dote upon; actually it's an old name for a streak plate—a hard tile used to test gold by the color it leaves behind when rubbed on the stone.

_{Horn coral — Geology Guide image}