Hi Marian. Zandrite is a doped glass and is probably the same
substance as the color-change glass that is also marketed as
Alexandrium. As long as you know that it is, indeed, a simulant made
in a laboratory, and that it is basically glass, with the same or
similar durability as glass, AND you like it (possibly the most
important criterion), then by all means, use it. Only, please make
certain that you disclose to any purchaser or recipient that it is
what it is. Also, because it is glass, which hasn’t the best
durability, you are well served by making pendants and earrings from
it. Most other types of jewelry which can be more easily knocked
about, such as rings and bracelets, will not afford glass the
opportunity to stand up to the beating they’ll take. Have fun with
your new discovery!
James