Approximate Composition
45% - Combined ilmenite, euxenite, columbite and rutile
27% - Monazite
14% - Garnet
3.4% - Other heavies including zircon, silica
These concentrates have all the magnetite fraction removed. 
The concentrates were run through a laboratory SX plant. The results confirmed at 40% TREO.
Concentrates are from a Colorado placer mining project. Concentrates were produced with Pan Am Duplex jigs and then gravity separation tables using gravity separation to extract the freegold; these are the remains.
Great for research, extraction projects, and as a collectible. Note they still contain some amounts of gold – these should run ¼ ounce a ton according to fire assay from Hazen Research. In addition, according to xrf analysis these concentrates do contain the suite of platinum group metals.
Radioactive, but will take a sensitive device to get a reading on such a small amount of sand. I have a high background but I would say about 500 up to 750 cpm above background is what I am seeing through the bag with a Radiacode 103.
First picture shows the vibrant, washed material. The others are taken from the more dusty bulk material.
 Wonderful for microscopy!