A Geoscience Digital Image Library

DescriptionThomsonite is a zeolite that forms tight acicular radiating clusters and sphericules as well as some blockier crystals that are found in the vesicles or bubbles of volcanic rock. The structure of a zeolite contains open channels that allow water and large ions to travel into and out of the crystal structure. The size of these channels controls the size of the molecules or ions and therefore a zeolite can act as a chemical sieve, allowing some ions to pass through while blocking others. The chemical formula for thomsonite is NaCa2Al5Si5O20ยท6H2O. It was named after the Scottish chemist, T. Thomson (1773-1852).
LocationUSA ▹ Minnesota. Near Grand Marais.
PhotographerShannon Heinle. 2001-03-26.
CollectionUniversity of North Dakota Mineralogy Collection #1862.
Key wordsthomsonite, zeolite, silicate
Tech details773 KB. Hand specimen. Fujifilm FinePix S1Pro digital camera; 60mm AF Nikon micro lens.
GeoDIL number266