what is the wood on the back of the bass

I haven't tried one of these yet, so here goes: I'd say Koa (which happens to be one of my favorites).
 
Looks to me like it's more than just the back, maybe most (all?) of the body - may we see what the front looks like now?

To me that looks like the standard mahogany body, although it has more 'action' than usual.  Other than a few that are special ordered from time to time, Alembics usually have mahogany bodies... the exception being the Excel model which usually with an ash body.  Other woods listed as options for body wood selection are vermillion, walnut, purpleheart and maple ( both regular & flame).
Bob, you can see the front of this bass following this link http://club.alembicguitars.net/Images/393/4706.html?1052975141
Sixstring, if you can get the serial # for Mica she'll be able to tell you the entire history of the bass.
 
Valentino

The link points to a left-handed Epic - but that Orion sure has a nice backside. It looks like mahogany to me! I guess sometimes you get lucky with mahogany, and sometimes you get some that just looks a little dull. On my Epic, it shows different shades of brown depending on the lighting - it can look really dark looking from one end, and very light from another angle. Not sure if the satin polyurethane finish has anything to do with that.

Is this a contest?  I would venture to guess that it is mahogany too.  I have seen stripey mahogany like this before and I have heard that it is called ribbon mahogany.

Alright, a contest! What prizes can you win?
 
Just kidding, of course.

That lefty 5-string Orion is offered by G Guitars in New Haven, CT.  
 
I have also hear this figuring referred to ribbon stripe figure.  
 
I like just about any piece of Mahogany, but the one on the back of the Orion that started this thread is particularly beautiful.

Okay, so I certainly didn't win anything - but at least we all seem to agree it's a pretty special piece of mahogany (could've been Koa...)

that just looks like nice 'figured mahogany'... there is also a mahogany-like wood called sapele that commonly exhibits big stripey figure  
 

(sapele)