Fluorescent Yellow Chalcedony/Chert from Milwaukee Co, Wisconsin. 188 grams.

Description

Grey, yellow and cream colored Chalcedony/Chert nodule with Liesegang bands and other fascinating details.
This may be some kind of fossil pseudo morph, but cannot say for sure. Naturally polished smooth from tumbling around in lake Michigan.
Portions fluoresce a yellow under long wave UV light (Convoy S2), not much to no reaction under short wave UV.
Found in Milwaukee co, Wisconsin along the lake Michigan shoreline.
I am not certain of the reactive element that causes it but possibly a carbonate mineral.
Chalcedony/Chert nodules like this are not that unusual of a find along the lake Michigan beaches but ones that fluoresce are.
188 grams.
2-3/4" in length.
NOTE!
Photos taken with a 365nm Convoy2 bandpass filtered Long Wave UV light, if you use any other type of UV light you may get different results.