>Dear isogeochemers,
>
>I am about to separate kfs-OVERGROWTH from Cambrian and Ordovician samples
>from the Appalachian Basin for isotopic analyses  ...  and I have some
>questions:
>
>1.       For heavy liquid separation from the other minerals,  mainly qtz
>and plag,

Another thing you might try, at least for separating quartz from the
feldspars (at least with crushed rock samples), is to sprinkle your grains
in a line along the edge of a sheet of plain white paper. Tilt the paper up
at an angle (supported by a piece of cardboard), and lightly tap or jiggle
the paper (sort of like a Wiffley table). Since quartz has no cleavage, the
grains tend to be more rounded and will roll off the paper. The feldspars,
with cleavage, tend to have at least one flat surface that will "stick" to
the paper. I don't know if this would help you with your needs, but it
worked pretty well for me.

Regards,

Tim

--  Timothy Thorpe Allen, Ph.D.   <[log in to unmask]>   "Tim"  --
--   Geology and Environmental Studies, Keene State College   --
--                  http://kilburn.keene.edu/                 --