Tumbling "Soft" Serpentine

[Roan]

I'm new to tumbling and bought an 18# serpentine rock that was listed as for cabbing, but I want to use it tumbled. I tried one batch and it was a disaster. The rock has a *lot* of yellow, which is what I want to keep, and it crumbled off The rest pitted. Blah. The slurry, throughout the entire process, was thick and foamy. I used pellets, but it didn't help.

Hints on tumbling this rock?

Eileen

[krazydiamond]

serpentine may be too soft to tumble polish. depends on the particular type you have, the MOH varies. got a photo?

KD

[Roan]

Feb 16, 2008 18:24:11 GMT -5 krazydiamond said:

serpentine may be too soft to tumble polish. depends on the particular type you have, the MOH varies. got a photo?

KD

Dang. Here's the photo from eBay:



If you need a better view, I can take some pics this evening.

Eileen

[deb193redux]

I think you will need to use a nail and scratch some different areas. Any that scratch easily with the nail should not really be tumbled.

[Sabre52]

Yes, unfortunately, most serpentine is a mixed hardness material which makes it very difficult to tumble because the soft areas undercut leaving an uneven surface....Mel

[Michael John]

Any material containing minerals of varying hardness is going to have problems, to some degree. The greater the difference in hardness, the more severe the problem. The same would hold true if you tried to cab it. The seller should have warned you about the variance.

[Roan]

Thanks, guys.

Yah, the yellow comes off very easily with a nail or any other metal object. It does file okay, so I might work it by hand.

As for the variances -- would have been nice if he had told me, however I should have known enough to ask. It's still a beautiful rock and I can still use it in my sculptures.

Thanks!

Eileen

[johnjsgems]

Might make a nice carving piece.

[Roan]

Feb 16, 2008 23:33:28 GMT -5 johnjsgems said:

Might make a nice carving piece.

I was thinking that and I might try it. I'm not conversant with carving anything harder than 6 MOHs. There are a lot of mineral deposites in this rock and those are a royal PITA to work around for me.

I may try it -- and you've just reminded me that I also have 75#s of Black Pearl steatite that I can carve

Eileen

[dshalldms]

My question is...

What range of hardness does Serpentine occur?

Following this thread reminds me of a piece of rock
that I picked up from the Fraser River, about 20 miles
north of Hope, BC.

This 56lb water warn pebble is shiny dark green
with black flecks. I have always thought of this as a
piece of Serpentine. However, a steel file will not
make any impression on. I tried to chip a piece off
with a geologists hammer, but that made no impression
either.

Perhaps it's not Serpentine after all! Back in 1968,
the then Premier of BC, Mr W A C Bennett, declared
the area... The BC Jade National Park. An area where
commercial mining was not allowed, but that individuals
might take small amounts for their own pleasure.

Just a thought.

Derek

[johnjsgems]

Serpentine is easily scrtched with a knife. Sounds like you found some jade Derek. If you use a loupe jade will have a fibrous look under magnification and usually a slight waxey feeling

[rallyrocks]

Derek- I'd agree with John, you probably have a piece of BC Jade.
Serpentines do cover a wide range of the Moh's scale but I don't know of any running much higher than 4.5-5 or so.

Ive come across some northern cal serpentines that will tumble OK up to about the pre-polish stage, but they are still too soft/fibrous/inconsistent to take a polish in the tumbler.