Thank you for the information you provide on determining real jet.  I have an old necklace that has faceted black beads, individually knotted with brown twisted cord.  I think it may be hair.

The beads leave a light brown streak on rough tile.  I have many 'french jet' glass bead necklaces that are heavy and cold to the touch.  This one is lightweight and warmer to touch which is why it caught my attention.  

Under magnification there are no 'seams' from  a mold.  There is a crack and a chip on a couple of beads, with a brownish color where the mark is.  I also found under magnification to needle marks - obviously someone did the hot needle test before!

What i noticed, however, is that when I hold the bead up in bright sunlight I can see a reddish glow through the bead.  I haven't read anywhere to hold up a jet bead to the light. I wonder if this is vulconite?

I am attaching a few pics.  Jet?
Thank you in advance!

kiki