Re: Re: Re: Garnets in the rough
The white coating may be a calcite or carbonate based mineral that could be dissolved away by a long soak in vinegar or maybe a de-scaler like Lime-away. The white coating should bubble if it is reacting. As a last resort try a 10% phosphoric or muriatic (hydrochloric) acid solution from the hardware store. The old timers used battery acid (sulphuric) to clean fluorite specimens, but I do not recommend this as it is unnecessarily dangerous. Hydrochloric acid�s high reactivity with water means it will produce an even worse burn on skin then other strong acids. Your specimen and matrix may be inert to the acid, but always test on a poor piece first to be sure. Sometimes garnets and other crystals are bonded together with veins of calcite. Handling acid can be dangerous so I have included some basic safety tips as a reminder. Remember to use safety glasses, rubber gloves, apron etc, but try not to rely on them and keep everything dry. Do not breathe any fumes as this can burn your nose, throat and lungs in the same way that WW1 phosgene gas killed people. Use only outside. Careful not to splash when transferring liquids and always add acid to water... never add water to acid!! If you add water to the acid it reacts hotly, can boil, spit, or even explode. Adding acid to water is a cooler process. Don't try to neutralize the acid if spilled on your skin as this would cause the acid to heat up and make the burn worse. Keep a bucket of just plain water for immediate treatment of any spilled acid. Don't let any metal utensil or metal container contact the acid. Be aware some plastics will melt in the acid. Never mix acid with other chemicals or cleaners as they can react violently, explode or produce poisonous gasses. Don�t store or leave acid around where kids or animals could get into it and keep containers labeled. Once the specimens have soaked in the acid and are sufficiently clean rinse them first in water then in a baking soda, water mixture to neutralize the acid soaked into the specimen and then a final rinse in clean water. Waste acid should be neutralized before disposal. Follow manufacturer precautions and disposal instructions. Good luck and be safe.
From Dan - July 17, 2008 at 08:12:08