Agate and Quartz SiO2 is a hard mineral, still it is my fun to light it from the inside..
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Looks to be Quartz combined with a jasper like protrusion both SiO2 and some compacted material that has been tumbled through geological time..
Picture focus does not allow detail analysis..
Other then a minor oddity there is no real value..
Here is a quarter of (an agate) geode that cost $2..
Which was tumbled then cut and finished..
You recognize agate also SiO2 <==> silicone-dioxide by those formation lines which under microscopic examination resolve into the thousands of lines..
thank you very much for your reply. I just gained a tremendous interest in stones/minerals signs their formation.