Here is a question I recieved recently about Lampwork Beads and think it would be helpful to everyone.
Q: I bought a set of lampwork beads in my local store  and  after I got home two of them cracked, they almost exploded.  I didn't droped them, they were laying on my desk and I heard a strange sound I turned around and saw  pieces of them laying next to each other  - what happened ??A: The beads you purchased were not properly annealed. It's a special  process of slowly cooling the beads after they were made.
All the glass beads are created  under very high temperature, once it melts and becomes very pliable special molds are used to create shapes.
During this process all the molecules inside the glass structure start  moving really fast and  as soon as glass starts taking the shape it is important  to  cool it down very very slowly to let these molecules to calm down again and keep that  shape.  For examle: when hot glass is taken out of the  hot temperature  into cold it cracks, that's because the molecules don't have time to adjust so quickly.
The process of slow cooling is called anealing and  hot glass is usually put into the kiln at a special temperature, which drops very slowly for a certain period of time ( depending on the size of the glass item).  Once it's done, the molecules inside the glass are rebonded and  the structure of the glass becomes more stable.
Lampwork beads have been produced for centures and  become very popular nowdays.  Today's Artists  are really going wild and creating  amazing beads, pendants and other shapes. No wonder, they've become a collector's item.
It all starts with a simple glass rod melted in  a flame torch  at a very high temperature, once it is soft  the glass is rolled on a steel mandrell.  There are so many different  techniques  to make it a desired shape, lots of different colors applied in layers and melted over and over.
It is a very slow process and requires a lot of skill to make a nice piece and make the glass to "behave".  Very intriguing too, because you can't really see the colors untill the glass  cools down.  So once the bead  is done, it is going into  the kiln  to cool down and  the result can be amazing !  ... But you never know....
Buying lampwork beads, pay attention to the following:
1. It's best to buy from the person who makes the beads. They know all about the process and you can ask any questions directly. Plus, every Artist takes a great pride in their own creation, so you know you are buying geniune quality product.
2. Check for visible cracks,  if you see at least one, don't buy it - the bead will fail aventually.
There are a lot of replica beads on the market today ( mass produced from the work of original artists - sometimes without their consent ).  These, usually, have not been properly annealed to speed up the manufacturing process.  Not only they detract from value of your jewelry piece, but can be dangerous, as they can sort of explode in peices at any time.
3. Check the bead hole. If you see a white chalky substance inside ( bead release, so the glass doesn't stick to the mandrell while hot)  it means it wasn't properly cleaned.  Serious artists clean their beads thoroughly before putting them up for sale.
In most cases it's an indication of a low quality mass production of beads.
These simple steps can help you to identify  good quality, original lampwork beads, which certainly  adds value to your design.