The pink beads look like glass. They have bubbles in them which is an indication that they are glass as opposed to a gemstone.

Not only are the pink beads made from glass; but the median equatorial lines indicate these are molded glass beads, composed from "satin glass." (The name "satin glass" can have any of three entirely different meanings, depending upon the glass and the context. If I don't say this I'll probably hear about it!) Molded glass beads are from Central European industries. Primarily the Czech Republic (formerly Bohemia and Czechoslovakia), but also including Germany and Austria.

Usually when a glass bead is heavier than expected, it is because the glass composition includes lead—which can be used to make the material more substantial, reflective, or to alter color(s).

(In antiquity, in China, barium was added to glass compositions of the Warring States Period—resulting in glasses that were heavier than others. Again, if I don't say this, I will probably hear about it.)

Your yellow beads are very curious. But I cannot say I recognize them.

JDA.

Thank you JDA,
I wondered if the lead content in the pink beads would point toward origins in a particular part of Central Europe - are the Austrians more likely to have used lead than the Czechs for instance?
I've had other satin glass molded beads that have not been this remarkably heavy.
My best,
Linda

That's a question I cannot answer. However, I highly recommend the writings of J'me Lynn and Guy, from Wild Things Beads—as they have considerable practical information about Central European bead industries.

This link will take you to one of their articles, and leads to others:

http://www.wildthingsbeads.com/article-gcbi.html

Good luck. JDA.

The Czech region of Jablonec was by far the largest European producer of molded beads. These look Czech to me. The specific type of glass, combined with the graduation on the strand is typically Czech. However, it is very hard to say be 100% sure on beads like this.