Agate

This is my image for Tiny Tuesday challenge.
It's little agate brooch, less than one inch long, we bought on holiday last year at the Antique Centre in Doune.
Not sure how old it is.
Checked with Mr Google that Agate would pass as a mineral this is what I found out Agate  is a banded, fibrous variety of chalcedony and as such is composed of silicon dioxide which is classed as a mineral.
Thanks to Jen/JensPhotos for hosting.