What is a Cotisso?

What is a Cotisso? Having never heard the name Cotisso before, I had to do some research to find out what they were talking about at the Effetre factory.  It seems that this is the name they use to refer to a chunk of glass that here in the U.S is called glass cullet.

Large chunk of yellow cotisso from Effetre

So why am I talking about cotisso’s (A.K.A. cullet)?  Because when Mike went over to Europe last October, he got the factory to let him pick out a bunch of different colors of these intriguing chunks of glass and Frantz Art Glass is now offering some of them up for sale.

Piles of cotisso (cullet) being stored on patio at Effetre factory.

I think cotisso’s are fabulous looking and look like surreal chunks of precious minerals.  I got a big batch of cotisso’s a decade ago after pestering the factory manager endlessly to let me pick out some chunks to include in the glass shipment we were working on at that time while we were on Murano, Italy.

I love the cotisso’s that I have and I set them on my worktables, in windows in my studio and house.  I also manicured several choice chunks by smoothing the sharp edges with a handheld dremel and I use them in my booth display when I sell my beads because the cotisso’s add such a delicious splash of glistening color to my bead display.

Effetre puts the more expensive colors of cotisso's in cans to keep close track of them.

You may ask why I smooth the edges of the glass chunks I have in my bead display and it is because they are so beautiful, people want to touch them.  To prevent anyone accidentally cutting themselves on a shape edge, I took a grinding tip mounted in a dremel tool and smoothed the less friendly edges off the glass chunks.

Another question I kept asking the manager at the Effetre factory is what do they keep them for?  The answer turned out to be very interesting!  When they measure out a new, from scratch batch of glass ingredients, it is all in powder form and is very slow to warm and melt into glass.  They introduce a few chunks of cotisso’s of the color that is being melted and the solid mass of the cotisso heats up much faster than the powder and speeds up the entire melt.

When the factory is done pulling rods from a new batch of glass in one of their furnaces, they move the last of the glass batch to a shallow cast iron bowl while it is molten hot and they set it outside on their patio and let the glass air cool.  The glass naturally fractures while it is cooling in the iron bowls and when it is completely cool, their turn the bowl over and dump the chunks of glass out onto the concrete patio.

Iron bowl of hot yellow glass cooling to become cotisso.

Three legged iron bowls of cooling glass.

Sometimes, the piles of cullet are very tall and they look especially beautiful when they are transparent and the sun shines through the glass sitting in the sun.

Transparent Aqua cotisso's.

Purple opaque cotisso's.

Don’t miss this chance to get a beautiful unique cotisso for yourself.

Group of three legged iron bowls for cooling cotisso.

Cotisso being stored in big plastic containers.

Group of opaque orange cotisso.