December

Agates in Rhyolite

Place collected:
Date collected:
Woodward Ranch, Texas
1966
  Putnam Museum and Science Center, Iowa, USA
EMu user since 2004

Agates in RhyoliteThis unusual specimen from Woodward Ranch, Texas, consists of multiple small, round, varicoloured agates in a lava matrix. It was part of a collection donated to the Putnam Museum by Mrs Carma Shorey.

The Wilson & Carma Shorey Collection is the source of many of the Museum’s more exotic mineral specimens. The Shoreys travelled the world, working with dealers, attending shows, visiting shops and collecting in the field. Over some 40 years the Shoreys created a remarkable gem and mineral collection, which Mrs Shorey donated to the Museum in 1986.

It seems likely that this specimen originated with trapped gas bubbles in solidifying volcanic material. Mineral-rich solutions then penetrated the spaces left by the bubbles and deposited siliceous material such as quartz, agate and jasper. Apparently the mineral solutions and / or the conditions in each cavity differed enough to create a suite of agates in the piece, including a dendritic one in the lower left side.

Acknowledgments: Putnam Museum and Science Center