Alexandra Norrskèn (N.S.) (lantichristo) wrote,
Alexandra Norrskèn (N.S.)

Rock Polishing

Well this post is all about Rock Polishing. It is long, thorough and has lots of details that most of you scum bags won’t understand or care about. So unless you are really into rock . . . POLISHING …. Do not read it!

For years now I’m collecting rocks. Specially those you find at a seashore. Every time a friend is travelling abroad I always ask them to bring me back a little stone. It is free, it is symbolic and it is unique, as unique as every stone. I’ve always been washing my stones and then run “shade” them with polishing paint. After this I’d place them around the house, in glass bowls and on ledges, but mainly I put them in my flower pots. They help the plants keep cool and they make the pot interesting and pretty. Recently I started thinking of going pro. I want to buy a Rock Polishing machine. I knew nothing about it though so my search was rather slow and confusing.

But now I am a bit more educated on the subject. I found out some fascinating information that made it even more interesting. For example I didn’t know that there are many steps using a machine and that the machine has to run 24/7 for about a MONTH. Here is this is a copy of a review:

Did you know that this process would take about a MONTH from beginning to end? Neither did I or my 8 year old ! At first, we were kind of shocked. But then it dawned on me that everything he does is about instant gratification, and when we started talking about this being worth the time, and how accelerated the process is versus it occurring naturally, we agreed that it was actually really neat.

You put in coarse grit for a week, fine grit for a week, pre-polish for 3 days, and polish for a week. You will use these up on one round of polishing with the machine, so save the brochure for ordering more (about $9 for all four). It comes with a decent amount of stones, and there is room in the rubber barrel for more if you have a collection you'd like to add.

Some machines are noisy, so if you live in a small flat then … tuff luck … but some others are described as super silent ….

I also found out that there are two main types of rock tumbler/polishers: rotational and vibrational.

A typical rock tumbler uses a slow rotating drum/barrel to polish rocks. It is inexpensive (around $30) but takes at least 4 weeks for the complete process. A vibrational polisher shakes the barrel vigorously to reduce the polishing process down to about one week, but they are much more expensive (over $100).

Vibratory tumblers won't take the edges off rough rocks like rotaries will. This can be a good thing or a bad thing depending on what you're planning to tumble and what end result you want to have. If you're wanting a smooth, rounded result from rough stones, you won't get it with a vibratory. On the other hand, if you want the rocks to retain more of their original shape, or want to polish softer stones, a vibratory will do it without losing near as much of the original rock as a rotary would (and something with low Mohs hardness, a vibratory tumbler is going to be much gentler on). Or, if you're planning on polishing metal (such as brass cartridges for reloading), a vibratory is the better way to go.

Just don't be misled by the claims of time savings into thinking that rocks you pick up while rock-hounding, or rough lots that you buy from a mineral shop, are really going to be all the way done in 'a matter of days' with this tumbler. If your rocks aren't already rounded and semi-smooth to start with, it's normally still going to take just as long (and sometimes longer especially with stones that are Mohs 7 or harder) for the first stage or two with a vibratory as with a rotary.

This above is a rotational tumbler.

These are vibrational tumblers.

Here is a page about a vibrating and a rotating tumbler and some interesting info on the differences between the two.


Some may prefer the vibrating one cause its less time consuming. Still, narrowing it down from a month to 17-20 days may still seem too long for people with short attention span. So, those people looking for instant gratuity should just go play video games instead. For the rest of us, however, a rock polisher can be both a fun toy and an educational tool.

I stress the importance of patience and ability to follow through a multi-stage experiment. Mark your calendar and keep record for the progress, and so on.

Here is an article about rock polishing:

“ The art of rock polishing has been around since time immemorial. It was there before man or animal walked the planet. It was done by nature. The rains were one of the greatest rock polishers. The constant erosion that occurred on the coarse rocky surface gave way to some masterpieces. But the winds of commerce have engulfed this phenomenon. Today it has become a profession. Rock polishing is a machine intensive industry. There are institutes that teach courses in the art of rock polishing.

Rock polishing is achieved via a process called tumbling. A tumbler consists of an electric motor, a barrel, and a frame with rollers. A pulley and a belt connect the rollers to the motor. To begin, the barrel is filled up to almost three quarters with stones of about inch to 1 inch in diameter. Silicon Carbide is then added in a proportion that is half the total load in the barrel. Water is also added. The basic procedure is to tumble the rocks with progressively finer grits and polishes until the desired shape and shine is achieved. As the barrel rotates, its contents collide, wearing down the stones. The stones then begin to erode. The rate at which the stone erodes will depend on the characteristics of the stone. Every day, stop the machine, remove some stones and wash them under clean water. Then allow them to dry and inspect them with a small magnifying glass under bright light. Clean out the sludge in the barrel. If the stones are pitted or cracked, return them to the tumbler, add the right amount of silicon carbide and water, and repeat the process. When your samples do not reveal these pits, cracks and hairlines, remove all the stones. It may take 4 to 6 weeks to finish a batch. Once the stones are perfected, comes the final part. A tablespoon of cerium oxide per pound of stones is to be added. Tumble for another week.

There are different types of tumblers in the market. A Rotary Tumbler is easy to use, less expensive and gives the rocks a good basic shape. A Vibratory polishes rocks quicker but cumbersome to use. Cost wise they range from about $50.00 to $800 depending on the usage. A stone-tumbling machine can be found in most hobby or lapidary supply shops.

There are some stones that are very difficult to polish. Only course grit or medium grit is use for one to three days when Wonderstone, which is a soft rhyolite, is tumbled. This produces nice rounded stones which show the colors and banding well. Sandstone, calcite, onyx, limestone, glass and obsidian also fall into the category where there may be veins in the rock that will not polish. Some types of rocks are brittle, which means that they tend to chip instead of polish. Other reasons for the stones to remain unpolished are process related. If the earlier stages are rushed, then scratches are left in the rocks that the later stages cannot recover from. If the tumbler and stones are not cleaned well between stages, then the grit from a previous stage could be scratching the rocks and preventing them from polishing. If you have a mixture of harder stones and softer stones in your tumbler, only the harder stones will take a high luster polish. Best results are achieved when all the rocks in a batch have similar hardness. If a stone breaks during the later stages of tumbling, the sharp edges will scratch the other stones, so remove it before the final stages of polishing.

Agate and quartz are very suitable for tumbling in a rock tumbler. Any rock with a hardness of 5-7 on the hardness scale will generally take a nice polish in a rock tumbler. If the rough rock has a glassy luster before polishing it will usually take a nice shine. If the rough rock has an earthy luster before starting it will generally have an earthy luster after tumbling. Tumbled and polished rocks have been very popular with hobbyists and collectors for generations. Finished stones can be collected and traded, or used for beautiful ornamental pieces”

Here is a link with some tips in Rock collecting:

Here are some direct links to purchase rock polishing machines:

Rock Polishing is immensely interesting and in the end really gratifying!!!
Whether you take it seriously or you just want to play.

If you are a gadget freak and don’t really care about the perfect results of a more expensive polisher, you might want to take a look at this little bugger:

If you are STILL reading this then you are the kind of person who’d enjoy rock polishing. And the kind of person I’d most probably like ;)

So, get you tools goin and let’s Roll some Rocks baby! ;)

GodDAMN, I HATE the word rock . . . brrrrrrrr. . . it always reminds me of smelly, filthy, lice-infested, disease-carrier, bloody hippies ……

Here are some pictures of some really pretty rocks:

This is
polished various colors of "South Dakota Prairie Agate" and "Jaspers" crushed in sizes from 3/4" to 1 1/2" in size.

This is unpolished crushed "petrified wood" in sizes from 3/4" to 1 1/2" in size.

These are "Apache Tears" from 3/8" to 1" in size.

Here is a select quality "Bubble Gum Agate".



and this is polished "South Dakota Bubble Gum Agates" and "Prairie Jasper". They are in sizes from 5/8 to 2" in size. They are already shaped by mother nature. Just a little more grinding for shape and polish.

And finally this is Dalmatian Stone

Ah well . . . this is my new obsession . . . If you have any tips . . . they are welcome.

Just spare me the geek/nerd comments.

Thank you and have a lousy day!


Alexandra N.S.

Tags: arts and crafts, geeks, rock polishing, stones

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