While it may look great in the photo, the photo really doesn’t do it any justice. The marble looks absolutely stunning in person.
The marble that I have is a dichroic vortex marble. There are many different types of marbles available from lampworkers (the artists that work with glass). These include implosion marbles, which are slightly easier to make, and vortex marbles. The word “dichroic” is used because the inside of the vortex uses a dichroic material – one that changes color if viewed from a different angle.
I first want to talk about how dichroism arises, as it is a property of the material in the marble (in this case, silver and gold). The glass the artist used for this particular marble is a dichroic glass. This glass selectively reflects light at a certain wavelength (color) at a certain angle. View the glass from that angle, and you’ll see that reflected light. View it from another angle, and you’ll see a completely different color. You can get a feel for how it works in the following diagram:
The artist has used Borosilicate glass, a type of glass with a softening point of around 1000°C. Thus, in order to make such a piece, he needs a high temperatureto shape the glass correctly.
The general structure of a vortex marble looks like this:
The piece consists of two hemispheres. The first is the transparent lens that creates the depth illusion of the vortex. The second holds the cone, which is the actual vortex. When artists make these marbles, they first shape the cone. They then apply a decoration to the cone. Then, they complete the bottom hemisphere by adding the rest of the hemisphere, shaping it along the way. Finally, they add the lens to the top of the cone to finish the piece off.
These marbles are really hard to produce because getting the depth illusion of the vortex is critical. It all depends on how well the artist is able to shape the cone. A bad cone shape ruins the depth illusion.
Hopefully that should shine a little light on how artists make these marbles. I took a lampworking class during my trip to the US that I thoroughly enjoyed and I did end up making a marble (although not a vortex marble). Working with glass can get a little tricky, but it also is a lot of fun.