Quick Tip: Petrified Wood

petrified wood example

Petrified Wood is Bullseye’s magical unicorn streaky.

Its unique combination of glasses results in dramatic internal reactions at full-fuse temperatures. Here are two ideas for making this glass sing.

Copper Reactions

 The Clear areas of Petrified Wood contain Red Reactive Clear, a style that reacts with select copper-bearing glasses, developing deep red hues where they meet. Neighboring sepia-hued areas develop a variety of rich, earthy effects.


  • The red reactions may continue to deepen with additional heatwork. Maintain color with lower temp slump firings and other cautious heatwork. The piece pictured below became darker with a 1225°F (663°C) slump firing.
  • Some favorite copper-bearing styles for creating a range of deep reds include 3mm Turquoise Blue in Opal and Transparent (000116-0030 & 001116-0030), Light Cyan Opal(000216-0030), and Robin’s Egg Blue Opal (000161-0030).
Displacement with Frit

 Sepia-hued areas of Petrified Wood strike with varying opacity and colors. Play up this organic effect with various grain sizes of Clear Frit. We used Coarse and Extra Large. The frit rounds out and sinks in, creating shallow pools.


  • Leave space between the grains and give them room to melt and displace the underlying glass.
  • Expect variation to occur within a single sheet and throughout production runs of Petrified Wood.

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