lloyd1wv
starting to shine!
Member since December 2010
Posts: 47
|
Post by lloyd1wv on Mar 6, 2011 10:09:37 GMT -5
Has anyone figured out a way to polish calcite? I know its soft but there must be a way. I gathered up some nice pink ornamental stone used to put around shrubs, etc. I put it through the Vibe with AO with no shine results. I run the polish cycle again with TO and still no results. I cushioned pretty well with ceramic and soap but it just didn't take a shine. Has any one been able to shine the stuff?
Thanks!
Lloyd
|
|
|
Post by deb193redux on Mar 6, 2011 13:13:53 GMT -5
some sort of buffing wheel with an oxide paste and a bit of heat - never in a tumbler
|
|
lloyd1wv
starting to shine!
Member since December 2010
Posts: 47
|
Post by lloyd1wv on Mar 7, 2011 8:48:58 GMT -5
Thanks for the advice! Appreciate you input!
|
|
stefan
Cave Dweller
Member since January 2005
Posts: 14,095
|
Post by stefan on Mar 7, 2011 11:10:29 GMT -5
Calcite and the tumbler are not friends! Basically you end up with a calcite slurry! And polishing works pretty good with calcite. I tried cabbing some but pretty much failed as the calcite was just too soft for my heavy handed ways.
|
|
|
Post by Hard Rock Cafe on Mar 7, 2011 11:48:20 GMT -5
Here's why it doesn't work in a tumbler, from wikipedia: "Calcite can be either dissolved by groundwater or precipitated by groundwater, depending on several factors including the water temperature, pH, and dissolved ion concentrations. Although calcite is fairly insoluble in cold water, acidity can cause dissolution of calcite and release of carbon dioxide gas. Calcite exhibits an unusual characteristic called retrograde solubility in which it becomes less soluble in water as the temperature increases. When conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together or it can fill fractures."
Chuck
|
|
learn2turn
noticing nice landscape pebbles
Member since February 2011
Posts: 77
|
Post by learn2turn on Mar 9, 2011 14:28:46 GMT -5
I still haven't figured out rock tumbling but I know a tad of chemistry and used to run a SW reef tank where Ca solubility plays a big part.
Seems to be that when CaCO3 dissolve, pH raises quickly to the point where it is no longer soluble. What if you added just a tad of basking soda to raise the pH of the slurry?
Of course, since I don't know tumbling, maybe there's some other reason it still won't work like it's way way too soft.
I do know if you put calcite in vinegar and let if evaporate, you get cool snowy crystals that are very fragile.
|
|
|
Post by deb193redux on Mar 9, 2011 14:33:08 GMT -5
tweaking the pH to prevent it dissolving is a very neat idea. I have a dim memory of something similar for cleaning iron off of calcite crystals without dissolving them. But I think soft still presents a problem.
Interesting idea.
|
|
stefan
Cave Dweller
Member since January 2005
Posts: 14,095
|
Post by stefan on Mar 9, 2011 20:14:35 GMT -5
Yes at a mohs of 3 it grinds into nothing in no time flat. Fyi in my last comment it should have said HAND polishing. Not and polishing (stupid droid keyboard)
|
|