Art deco necklace, possibly Czech piece

Here is a question for plastic jewelry lovers.
I went through some older stuff I have today and decided to share this pretty necklace, which I think is art deco. It is cca 63 cm long. It has 2 types of plastic beads - I am not sure about the black beads, they are light and just "plastic". The orange beads are interesting. They are heavy, and the holes appear to be drilled manually into them (check first bead on picture 3). Also, the some beads are darker around the hole - why is that? Did they maybe heat the beads back then during the necklace manifacturing? At first I thought this is some cheap plastic, but now I think that because the beads are heavy, uneven, and because the hole is drilled manually, this might be some "good" type of older plastic.
When tapped together, they give a nice high sound.

1. Ceramics?
The beads are cold. Colder than the black ones. I thought that this could be even ceramics, due to heaviness, but what about the manually drilled holes? I dont believe someone would do this to a ceramic bead. It indeed looks like someone drilled the wire through the bead painstakingly, there is no space, like the bead originally had no hole. Weird.
(like the wire was glued inside to them, you cannot move them freely, you cannot move them at all on the wire).

2. Galalith?
Simichrome test was negative.
I tried to do the smell test - at first it did not smell like anything (which could be the lucite, but lucite is light, this is heavy), then I smelt something that could theoretically be wet wool - so - I think this might be galalith. But the smell was faint, not strong. I am a beginner with this type of test :) Shouldnt galalith smell be strong? What about the manually drilled holes and darker material around the bead hole? Is this normal for such beads?
Can galalith be cold? Its a plastic, so it shoudnt be...?

I would be very thankful for your opinion on the material.
I could do better photos of the bead holes tomorrow, if needed.