[Rockhounds] Re: Rockhounds Digest, Vol 43, Issue 9

[Rock Currier]

Steward asked:

I know how to clean bulk quartz crystals using oxalic or muratic acid. Will
the same process work on Jeffrey quarry solution quartz with cookeite on
it....or will the acid remove the cookeite? Your recommendations will be
appreciated.

First of all, are you sure it is cookeitt on the quartz from the Jeffery
Quarry?. If I remember correctly, the typical association is ankerite, a
carbonate mineral. Cookeite is a mica and not usually found associated with
quartz from sandstones, like those found in Arkansas. Take a bit of the
"cookeite", crush it to a powder and put a drop of hydrochloric acid on it.
If it bubbles, then it is not cokeite and cleaning the specimens with oxalic
or hydrochloric acids will remove or alter the "cookeite". If it is
cookeite, acids will not hurt it very much, but if you don't neutralize the
acid after cleaning you may turn the cookeite yellow with iron oxalate or
iron chloride. Are you trying to remove iron staining from the specimen? You
may wish to consider the use of Iron Out or Super Iron Out, which is a
commercial cleaning product sold in stores like Wal-Mart. It is sold in
gallon containers and is a fine powder that you pour out into water,
following the instructions on the container. Soak your specimen in that
solution and the iron stain should go away. This solution will not hurt any
calcite or other carbonate minerals on the specimen. The solution is almost
PH neutral and very easy on delicate minerals, even things like hemimorphite
that even weak acids will damage or destroy.

Rock