Line a baking sheet with parchment or wax paper.
Mix all ingredients together in a medium sauce pan. If you are adding any color or flavoring do so at this time.
Bring mixture to a boil stirring constantly. Once boiling stop stirring and let it cook until the thermometer reaches 300 degrees.
Remove from heat and immediately pour onto your prepared baking sheet. Allow to harden and cool (about 2 hours).
There are a couple different ways to break the candy glass. If you are not particular on the sizes and shapes you can lift the pan and drop it down on a flat hard surface. You can continue to do this until the pieces are a desired size. Another option is to break the pieces by hand. By lining the pan with parchment paper this allows you to easy pick up the glass and break it by hand.