Geodes: the "hole" story

Article Abstract:

Geodes are roundish rocks that contain crystals and occur in sedimentary and igneous rocks. While geodes are always perceived to be hollow, this is a misconception because there are geodes that are made of solid mineral. One of the most well-known geodes are those that come from Keokuk, IA.

Evaluation, Natural history, Geodes, Keokuk, Iowa

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Spectacular spectrolite

Article Abstract:

Spectrolite, a type of labradolite was first found in Ylamaa, Finland during World War II. Finnish geologist Aarne Laitakari reasoned that the source of labradolite and its varieties was actually Finland although it was first found near St. Petersburg, Russia near the Finnish border.

Finland, History, Natural resources, Mineral deposits, Mines and mineral resources, Mining

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Extraterrestrial sources

Article Abstract:

Meteorites are the extraterrestrial sources of gemstones. Diamonds have been found in meteorites, though none of these were of gem quality. A brief background on the structure and properties of meteorites is discussed.

Composition, Meteorites, Precious stones

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