Black, black, or black
 

I bought out a lady and I'm sorting the glass. There are maybe 30 pieces of black but only a few labeled. Eff064, Eff066, and one CIM.
How can I test these so I can label them correctly?
And I'm confused by Transparent" black. All the other Transparent rods are actually transparent, but the black isn't yet 064 and 066 are classified as transparent.

If you pull a fine stringer/hold the rod end up to a bright light and look at the cut edge, you will see the 064 is really a very dark purple. 066 is darker still (intense black) and stays black looking, but "webs" if you put a fine stringer on some glass (white, ivory, other soft opaque glass)
I'm not sure about the CIM. Do you know if it is Tuxedo or Hades? I think Hades will web too.

The label just says "messy black".

Either Tuxedo or Hades, then. Both are quite good blacks, and Hades has some nice reactions with silver glass. Try it with a silvered ivory stringer and see what happens.

I think between Hades and Tuxedo, the two Messy blacks, Hades is the denser black.

When you pull a very fine stringer of Tuxedo it is blue. Not sure about Hades.

People often refer to 066 as “intense black” or “IB.”