Well... Experiments with Cholla met with mixed results. Picked the ugliest piece in the box to play with, and educate myself.
First lesson learned - Cholla is extremely dense, it will not soak up stabilizing resin, and therefore you cannot dye it! Was hoping to dye the cholla and fill with different color resin. Ain't happening!! Mixed up 1 batch blue dye, 1 batch green dye - 10 drops to 100 ml resin. Pulled this down to no bubbles coming and let it soak under vacuum. Pulled to no bubbles 2 - 3 more times over the course of 2 days, put it in the pressure pot and held it at 50 - 90 PSI for 4 days, pulled it out, and cooked it off, and basically in a week's time I dyed the dead stuff on the outside of it. Trimmed the end off and there was NO penetration. Hit it with 180 grit Abra-Net and in about 3 passes we were back to bare wood.
So I loaded up a batch of Alumilite, 100 ml with two drops of Alumilite Blue, which is really blue!! Whipped up a couple of tin foil molds, and cast it! And, wound up with...
Camera batteries died, so these two were with cell phone!
I also learned the easiest way to set this stuff up to bore for pen tubes, is to put it on the sander and sand it down to cholla, leaving yourself with a little square blank centered around your cholla. Just way easier than trying to bore the center any other way after casting it. Again, this was the ugliest piece of stock above, a few missing pieces in the skeleton, but someone will thinks it's cool, so I made keychains out of it, rather than waste the time and material.
Had a good bit of resin left when I cast the above blanks, so I quick grabbed a short pen blank, and another piece of tin foil, wrapped the blank with foil to form a mold, grabbed a piece I'd trimmed off another blank that probably should have been thrown away, but we do don't do that in this insane game, and I cast another keychain blank.
After I got done and saw how it turned out, I was kicking my ass for NOT trimming this to turn a letter opener handle out of cause it's really kinda cool, and it's a 1/4" too long for that! Resin was too dark, cut the grooves to allow a little more light in and brighten it up a bit.
Then I took some of the peanuts
@barry richardson sent with the cholla and turned a Gatsby to familiarize myself with assembly of that pen, since this is the first one I've put together. Looks pretty damned good for peanuts!!
Unless I'm mistaken this is Eucalyptus Burl, with a little lace. Unfortunately most of the lace turned out of it. Was interesting to turn, to say the least. Lots of checks, lots of voids to fill, pieces flying off about the time I got it turned to finished size... No I was not impressed when I felt it fly out of there, and it looked awful close to ugly, but it did turn/sand out and didn't affect anything. Was still a lot of checks and voids to fill though!
Because of that, finish is CA and BLO. Attempts to wet sand kept leaving nasty white dust in the checks and voids, so I wet sanded with BLO instead because it darkens the dust, and thus helped fill the checks and voids with it. Yee Haa!! Lost count, 20 - 30 layers of CA, wet sanded real frequently. But it's purty!!
she'd be runnin off screamin about getting cooties and such just peekin in the door! Ain't no way you gonna get her all the way in there, and in a compromised position on the counter!! 
