You use oxalic acid to clean the rust (hematite) coating off quartz.
You use two table spoons to a quart of water. It works faster in a
crock pot on low to medium heat. Put the crystals in cold let warm
up and let cool down before removing. As far as I have been told the
amount of acid is not an exact measurement. I was told that after a
few uses the water can turn yellow and stain your crystals. I have
not had any crystals stain. I just discard when the water turns
yellow. I leave them soak for a few days to a week. I do not always
get around to checking up on them. I have never had a problem. I got
my Oxalic acid from shows and spent too much money. I tried to buy
it from a chemical supply house but they only sold in bulk. Then I
found out you can buy it dirt cheap at the hardware store. It is
Wood Bleach. Looks and works just like the expensive stuff from the
show. I hope this helps. John Daly Grand Junction, CO.