Banded Amethyst - With Milky and Smoky Quartz
This image shows a 3-pound bag of banded amethyst tumbling rough, dumped into a colander and sprayed with water to reveal its full color. Click on the image for a larger view. Wow!
Banded Amethyst Tumbling Rough
Size: mostly 3/4 to 2 inch pieces
We are selling three-pound bags of banded amethyst, specially sized for rock tumbling. Each three-pound bag contains mostly pieces that are between one inch and two inches in size. The exact size varies from bag to bag. There are usually about ten to twenty pieces per pound.
This material consists of beautiful purple amethyst, white milky quartz, and a small amount of gray smoky quartz. These three materials are banded with one another into beautiful patterns. A few pieces are zoned crystal fragments that when broken display the popular "V" shaped pattern known as "chevron amethyst." Look at the photo at the top of this page to see a few "chevrons." These make beautiful tumbled stones. Crafty people use tumbled stones of banded amethyst as attractive pendants, pocket stones, key chains, accents for potted plants, display gems for their homes and much more.
This banded amethyst is mined in Namibia, a country on the western coast of southern Africa. Namibia is a difficult place to live or explore for gems because much of it is covered by desert. It is one of the remaining parts of the world where a wide variety of semiprecious stones are still being found.
Here's what banded amethyst can look like when it is polished in a rotary tumbler. Nice zones of purple amethyst separated by bands of milky quartz and sometimes a little smoky quartz.
How To Tumble Banded Amethyst
Like most crystalline quartz, this material is easy to tumble into beautiful polished stones - if you know one important fact. That fact is: pieces of quartz of about an inch or more in size will bruise one another in a tumbler. To prevent that from happening, they should be surrounded by generous amounts of ceramic media or small pieces of rock. For the best chance of success, we recommend using about 50% ceramic media or small pieces of rock and 50% banded amethyst. When we say 50%, we mean it. If you use that much you should have good results. Use much less than 50% and your tumbled stones will have chatter marks around their edges. Small ceramic media provides the best protection, but a mix of large and small media will usually work well.
Also, don't underfill your tumbler barrel. A rotary tumbler barrel filled incompletely will have rocks being tossed around inside. Bruising will be the result. In rotary, your barrel should be at least 2/3 full and no more than 3/4 full when you tumble. Watch the video here to see what happens in an underfilled barrel.
You also need a properly filled bowl when tumbling crystalline quartz in a vibratory tumbler. An underfilled vibratory bowl will vibrate vigorously, and the rocks in the bowl will hammer against one another. If your vibratory stones have chatter marks on their surfaces, then it is likely that your bowl is underfilled or you didn't use enough media or small-size rock for cushioning.
Rotary Tumbler Suggestions:
Step 1: Fill the barrel 2/3 to 3/4 full with a mix of 50% media and 50% banded amethyst. Add two level tablespoons of coarse grit per pound of rocks, and cover the rocks completely with water. Then tumble for a two or three weeks - or long enough to shape and smooth the stones.
Step 2 and Step 3: These are the medium grit and fine grit steps. Again, fill the barrel 2/3 to 3/4 full. If your volume dropped because of loss in the coarse grit step, add some additional media to bring the barrel up to proper level. Use two level tablespoons of grit per pound of rock for each of these steps. Add enough water to almost cover the rocks and tumble for one week. Don't over-tumble at this step. If you allow the rocks to tumble more than is needed, you run the risk of bruising.
Step 4: This is the polishing step, so be sure that the rocks and media and barrel and lid are extra clean. Also, make sure that the barrel is filled to proper level. Add more media if needed, but if you have to add more media be sure it is clean POLISHED media. Dusty media or media that has not been broken in and smoothed can scratch up your tumbled stones at this step. We use two level tablespoons of TXP aluminum polish for each pound of rock. Add water until it almost covers the rocks, and tumble for one week. If your rocks need burnishing after the polish, run them in soapy water for no more than thirty minutes.
Vibratory Tumbler Suggestions:
Step 1: We fill the vibratory tumbler to the fullest capacity recommended by the manufacturer. If you fail to do that, the tumbling action will be too vigorous for crystalline quartz, and bruising will probably occur. Do this for every step of your tumbling with crystalline quartz. We use 1/2 tablespoon of medium grit per pound of material in the bowl. We also add just enough water to make the grit stick to the rough at the start, then as tumbling progresses we add water to maintain a thin muddy slurry. We rinse the rough and add fresh grit and water every 48 hours or as needed. Tumble for as many days as are needed to smooth the surfaces of the rocks. Don't overtumble or bruising will occur.
Step 2: We use fine grit for this step and tumble two days. We use 1/2 tablespoon of grit for each pound of material in the bowl. Start with just enough water to make the grit stick to the rock and tumble for two days, checking often to be sure that the moisture content is right. Your volume probably dropped during Step 1, so you should add enough ceramic media to bring your bowl up to proper operating level. This media should be broken in and free of factory edges.
Step 3: We use TXP aluminum oxide polish, but many people use #61 Rapid Polish for almost all of their vibratory tumbling. Tumble for two days in polish. Check frequently to be sure that your moisture level is right and to monitor the progress of the polishing. Expect it to take two days, but stop if you achieve a great polish in a shorter amount of time or go a little longer if you think it will improve the polish. Too much polishing will produce bruises on crystalline quartz. Burnish for 30 minutes in soapy water if needed.
What is Amethyst?
Amethyst is one of the top ten most popular gemstones across human history. It is found in many parts of the world and is abundant enough to be relatively inexpensive. People love its purple color. Few other gems compete with amethyst on purple color or on price.
Tumbled Banded Amethyst Available
We usually have medium-size (5/8" to 1") tumbled stones of banded amethyst for sale to anyone who would rather purchase finished stones than run a tumbler. You can find them here.
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