Raven, 9749 is our densest black.  This color can be pulled down to a fine stringer and it still maintains its color saturation.  For a saturated black, this is a surprisingly easy color to melt and shape.  It does contain chrome, so be sure to take this into consideration.  If you want a chrome free black, check out Eclipse, 9977.  Eclipse is less saturated than Raven, but is a highly workable chrome free black.
 
Working Tip: Work in neutral flame. If you flash heat in a reducing flame as you finish the project you can produce a look similar to the sheen of a raven's wing.
 
Artist Description by Mike Shelbo:
"This super saturated opaque black is the answer to your need for thin stringer work and dense overlays that need to be black when blown out thin.

It handles nice and smooth, also a bit stiffer than some other opaques but not by much. Raven can not be worked in heavy reduction for long periods of time without encasement. When used in a neutral flame in the correct region of the flame, this color will respond well and leave you with a beautiful finish. Treat Raven as you would other GA Crayon colors and you will get clean results.

Great for backing marbles, deep encasement, inside out work, and stuff and puff techniques. I like using Raven with so many other Glass Alchemy colors, but my favorite combo is with Haterade for encalmo work." - Mike Shelbo