ROCKHOUNDING

 

I've been collecting rocks for years.  I've lived in England and in various places here in the States, including Arizona.  I was always fascinated by what the inside the of rocks looked like.  An old rough rock many times contained a hidden treasure.  I learned that taking a spray bottle with water sometimes showed which ones had more potential.  Others are more difficult to spot.  The rock below shows how the colors can be brought out with a little water:

This is the same rock.  I had cut this one with a tile saw.  A little water makes it look completely different.  The exterior was the same way.  After rough shaping on the saw, I'll put it in my rock tumbler and the polishing process will begin. 

I'm still a relative newbie at collecting & polishing rocks.  Knowing how some look in the rough takes experience.  I had camped in New Mexico many years ago.  I took an ATV and rode to the top of the mountain in search of rocks.  Specifically, Apache Tears.  I didn't see any of the black rocks, but there was a bunch of silver looking ones.  After almost giving up, I picked up one of these silver rocks for closer inspection.  It was black on the bottom.  Hmm.  I held it up to the light, low and behold, it was an Apache Tear.  This looked nothing like I expected as I'd only ever seen them after being polished.  Now I knew what to look for.  When I looked down again, there were thousands!  The road was literally paved with them.  I grabbed a double handful before the thunderstorm chased me off the mountain top.  I had to leave early the next morning, and haven't been back since 1989.  I still know where this place was, and plan on going back someday.  Don't ask!  Point is, you may be walking or driving on some nice material, but it looks different in the raw form.  So occasionally crack some rocks open, or at least pick them up and give them a closer look.  No telling what you've passed up.

Now I live in Florida.  No rocks here, so I've been buying some rough material online.  I also have a box of larger rocks I had never done anything with.  These were too big for the tumbler.  Smashing them with a rock hammer wastes so much material.  There are some fancy dedicated diamond saws designed for slicing up rocks.  They tend to be expensive, and heavy duty.  I have a limited source of rocks.  This Workforce Tile Saw from Home Depot was only $88.  It does a very nice job of slabbing stones.  Learned this trick from the gang at the Rock Tumbling Hobby website. 

 

This saw made short work of my hardest rocks.  I now have a years worth of material in my rough rock box.  Here's a few I just chopped up, heading for one of my tumblers:

The next phase for me will be getting into shaping rocks, such as cabochons.  Again, there are dedicated machines for making these.  The trick on the website mentioned earlier is to use a standard bench grinder with a silicon carbide grinding wheel.  Not tried this yet...

 

 

 

Ongoing Projects

 

 

A few choice rocks collected from a special place.

The first phase of polishing these hard rocks is to use 60/90 grit to shape them, which removes all the rough edges.

The barrel should be filled 2/3 to 3/4 full.  Then put in enough water to cover the rocks.  Finally, add the grit, seal the container, and get it started.

The Lortone brand barrel in the foreground, the knockoff Harbor Freight one in the back.  So identical, either one will fit the tumbler perfectly.  I'll use one for the course stages, the other for the polishing stages.  This will prevent contamination. 

I have a more expensive Lortone rock tumbler, but this $30 model is sold at Harbor Freight.  The drum is interchangeable with the Lortone tumbler.  This unit gets quite hot, so I'll likely modify it later with some vent holes and a small fan.

UPDATE:  Within days of the first use, the belt broke.  VERY common issue.  I've ordered new ones from Ebay.  The replacement ones are a different brand, and should last quite a while.  I've also discovered that the barrel, while the same size, is a poor copy of the Lortone one.  The barrel is thinner, and quickly expands with gas buildup from the grinding process.  The clearance is very tight between the barrel and the tumbler case.  Once the barrel swelled up, the barrel contacted the case, stopping the tumbler from turning.  I put the Lortone barrel on it, and it's worked perfectly.  So I've ordered a spare Lortone barrel, and will keep the stock barrel for a backup.

My trusty old Lortone Tumbler.  Getting a little ugly, but still works great.  Only recently broke the original belt.  A few spares on order.  Should be up and running shortly.

This process takes weeks.  Usually a week or two between each of the 4 phases.  After the 60/90 grit, thoroughly clean the stones, then run with 120 grit.  Next, thoroughly clean the stones again, and run with pre-polish.  Finally, clean again, then use the polish.  Very important that the stones & barrel be cleaned between steps.  Any left over abrasive from the previous step will ruin the following one.

Here are the same rocks after the 120 grit phase.  Shaping up nicely.  The rough edges are gone.

As the rocks polish, material is ground off.  Consequently, the volume of rocks diminishes.  Also, the rocks can be easily chipped with more space to fall as the tumbler turns.  After the rocks and barrel had been cleaned, I put in the rocks, the polish, and plastic beads.  Important to keep the barrel 2/3-3/4 full.  I added the required water, and set it loose.  We'll see how they look in another week.

In the meantime, got another tumbler on order.  After I started slicing up the stones from past trips, I now have a bucket load to polish.  It would take a year to do all these in a single tumbler.  I'm getting a Lortone 33B, a double barrel version of the 3A that I already have. 

 

 

Can't wait until my next trip out West to get some more material.  Until then, my garage has a happy hum of tumblers... at least until I run out of material.  Check back for updated pictures.

 

 

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Last updated 05/08/06    All rights reserved.