Dear Karen and isotopers,

As an alternative method to heavy liquid separation, this paper (see 
below) describes a magnetic separation method. Quartz+feldspar mixtures 
are treated with HF, the feldspar is etched, quartz remains intact, then the 
sample is mixed with magnetite powder. The magnetite grains are stuck onto 
the rough surface of the feldspar and thus it could be magnetically separated 
from quartz. The questions might be: is there an effect on the d18O of the 
feldspar? can the magnetite be removed perfectly after the separation? I think 
it might be worth trying.

Iacumin, P and Quercioli, C. (1993): A new technique for quantitative 
separation of quartz from feldspars. Eur. J. Mineral., 5, 677-678.

Cheers,
Attila


Dr. Attila Demeny
Laboratory for Geochemical Research
Hungarian Academy of Sciences
Budapest, Budaorsi ut 45, H-1112, Hungary
tel/fax: 36-1-319-3145
e-mail: [log in to unmask]