Invertrypa Brachiopod

This brachiopod fossil from Middle Devonian Period (about 390 million years ago). Fossil was found near Louisville Kentucky, USA. Brachiopod is an Invertrypa sp. from Jeffersonville Limestone of Clark County, Indiana.

Florissant Plant Fossils

Recently, my cousin returned from Florissant, Colorado with this fossil plate from the late Eocene Epoch Florissant Formation as a gift.  As best I can tell the first fossil shown is a leaf of maybe a Fagopsis or Cedrelospermum.

The next picture appears to be a piece of white cedar (Chamaecyparis) tree. Thanks again to Kenny for the gift.

UV Fluorescent Brachiopods

This fossil plate of a cluster of Sowerbyella (Jones, 1928) brachiopod shells appears to have a unique property of fluorescence under longwave ultraviolet light (394? nm).  My light produces a lot of visible purple light so the specimen appears quite purple with some orange-brown color on some shells.  In person, the orange-brown color is much more pronounced.

I believe the mineral present is aragonite with a manganese activator.  Referring to the book The Uranium and Fluorescent Minerals: A Handbook of Uranium Minerals and A Field Guide for Uranium Prospecting 3rd Ed. by H.C. Dake, page 21, it lists "ARAGONITE. A calcium carbonate that fluoresces and phosphoresces variably.... When manganese is the chief activator the luminescence is orange or red-orange, and usually faint."

These fossils are from the Kope Formation (Edenian Stage, Upper Ordovician Period) of Kentucky USA and that layer is known for its aragonite fossils (usually brown).  I need to now go through the collection and test them for fluorescence.

Another issue I need to solve is filtering visible purple light from my UV light. I might have to go Thomas Edison on it and just start trying different materials for filtering properties.