Ken,

Attached are the XRF, optical, ?reflectance and assay runs on the parking lot calcite pieces you sent me..

The optical spectra shows a center wavelength at 610 nm ?(orange-red) with a pronounced tail into the near IR. It has a good red Phosphorescence of about a sec decay under a 405 nm laser. The red is seen in the 405, 365 and in the 256 nm short wave but longer wavelengths are stronger. I couldn’t measure the fluorescent lifetime as that optical bench is pulled apart right now, but it does have a nice red decay.

The Reflectance spectra show a 50% reflectance monotonically decreasing to 45% in the red to NIR. Pretty much a white rock with no absorption centers.

The Calcite 50kV spectra show no rare earths at the higher energies. ?The Calcite 40 kV spectra indicate the expected Calcium (Ca) of the CaCO3 but also included Fe, Mn, Sr, Pb and Y.

The Assay was run with an Olympus DP4050 XRF in the Soil REE mode as we were looking for activators in the ppm range. That mode will over report % level elements (Ca).

The valid elements detected are Ca, Mn, Sr, Y, Fe, and weak Pb, Cu and Zn. The others are interferences from peak overlap and should be ignored.

In General, the activators for calcite are most commonly Mn+2, Fe+3 UO2+2 and the rare earths. The red emission and phosphorescence is most likely caused by the Mn+2 and Pb+2. This occurs in calcites that are hydrothermal in origin. A green fluorescent calcite is usually due to the uranyl complex.

The only surprise is the Yttrium (Y) which is about 10 times what I would expect to see.

Find some big pieces or better yet find out where it came from – that would be a good collecting/field trip.

Dud KK7IF

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