"Pinfire opal" is a name used for opal that has pinpoints of fire throughout the stone. The opal on the left is a pinfire opal cut from material mined at Coober Pedy, Australia. The stone on the right is a pinfire opal from the Constellation Mine in Spencer, Idaho. It is 6 millimeters by 4 millimeters in size. The video below illustrates the "play of color" in a pinfire opal.
Sunstone: a feldspar with aventurescence caused by light reflecting from platy inclusions.
Volcanic Explosivity: Rating volcanic eruptions based upon the volume of tephra ejected.
Salt Glaciers are masses of salt that flow downslope under their own weight.
What is a Maar? The second most common volcanic landscape feature on Earth.
Minerals are the building blocks of our society. We use items made with them every day.
Rocks Galleries of igneous, sedimentary and metamorphic rock photos.
The opal on the left is a pinfire opal cut from material mined at Coober Pedy, Australia. The stone on the right is a pinfire opal from the Constellation Mine in Spencer, Idaho. It is 6 millimeters by 4 millimeters in size.
