Re: Field determination of the dolomite % of chip samples
Have you tried staining with Alizarin Red and estimating the % of rock that turns red? The dolomite won't stain. If there are other minerals in your sample they may or may not stain but this is pretty much the standard mud loggers test.
Page 37 of Well-Site Geologist's Handbook by Donald McPhater and Brian MacTiernan, published byPennWell Publishing Co of Tulsa Oklahoma 1983 has a table that lists the colors various carbonates stain using a solution of 0.2% HC, 0.2% Alizarin Red and 0.5% Sataurated Potassium Ferricyanide. But I just use a commercially available solution (concentration unknown - not on lable) of Alizarin Red and get pretty much the same results.
Roughly speaking the table is as follows:
RED - pure calcite
Mauve - Ferroan Calcite Fe oxidation state +2 poor
purple - Ferroan Calcite Fe oxidation state +2 rich
Light Blue - Ferroan Dolomite
Dark Blue - Ankerite
Unstained - pure dolomite