A brief lesson in slab thickness for moss and plume agates

I didn't say which was best, although if you assumed that I like the thinner better, you're right. 

A lot of MT agates look transparent (colorless) when cut thin enough, look blue when cut at a certain thickness, and look colorless but opaque when thick enough.  So besides the issue of how well you can see the moss / plumes, color changes as well.  Cutting angle effects this too, since MT agates usually have bands even though you can't see them unless back lit.  The bands are more transparent from some angles than others.  Lots to think about when cutting.

HJ, you know your Montana but I don't understand what you are saying other the thinner the slab, the more light passes through it. The thickness of the slab changes the amount of attributes in it. A thick slab with a lot of dendrites won't have the spacing between them. I do a poor job some of the time getting a 1/4 inch and usually want to err to the thick side. A preform can be subtracted from but not added to.

Here's an atypical Montana where the grinding dictated the pattern, not the original slab thickness.

Well...I'm enough of a newbie that I appreciate threads like this!

It's something I was noticing when I was working Graveyard Point Plume Agates. I know...this is about moss...not plumes! LOL - Kidding, I know it's the same concept. Anyway...I realized that I had cut some of my slabs far too thick. One of the issues I realized was the "waste" of the plumes. With the thicker cut slabs, half the plumes can't be seen...they're buried. So, with a thinner cut slab, I was conserving plumes for the next slab. Also with the thinner slab, as you pointed out, light penetrates better and I think it allows for the plumes to show up better.

That was a really long-winded way of saying "I agree"! LOL

What a great visual to show there is a distinct difference amongst those three thicknesses!

Stinking Water comes in different qualities. Very clear agate with distinct plumes can be as thick as a brick.

But does the thinness of the slab impact how big you can go with a cab with material like this?

If you're making a cab with a biggish amount of surface area, I'd imagine the slimmer slabs might be more prone to cracking or spalling while cabbing, whereas thicker slabs might hold up better?

I like big cabs and I cannot lie.

It depends on your skill level and experience, I suppose.  Thinner slabs means lower dome cabs.  No way around that.  And a low dome on a big cab is more difficult than a high dome on a big cab, which is more difficult than a high dome on a small cab. 

It probably took me 100 cabs of experience before I could reliably put a low dome on a big cab, and it still doesn't always work out perfectly. 

I usually don't cab any material that is so unstable (fragil) than slab thickness would make a difference in terms of what the cab cracks.  A very thin slice of a solid agate -- say 1/8" thick -- is incredibly strong as long as you don't drop it. 

Good questions.    

It looks like someone else (deleted member) had the same experience with Stinking Water plume agate:

forum.rocktumblinghobby.com/post/1051128/thread

I guess I don't see where he posted anything that was "standard" other than the first 1/4" cut slab - which is pretty much understood as industry "standard" for thickness of slabs.

If a person isn't cutting their own slabs, then yes, they can "thin" their cab to obtain whatever effect they're going for. 

Jonathan was trying to show examples for people who DO cut their own slabs. He was giving extremely good advice with regards to something "newbies" should be thinking about or considering when they're choosing their depth of cut on certain materials. If all material were cut "standard" and then thinning their cabs, they're just wasting material! If the slab were cut right from the start to the thickness - or thinness required for the desired effect, then "thinning" the cab isn't necessary.