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The Gitchee Gumee Agate and History Museum in Grand Marais owns a collection of marbles made from Lake Superior agates.
The museum also offers rock-hounding classes, where participants begin at the museum and learn about identifying agates, then head to the shores of Lake Superior to search for the stones.
A 1902 article in the Detroit Free Press stated that many imitation agate marbles "that [wore] holes in the pockets of schoolboys" were made in Germany.
Examples of Brazilian agate and onyx cut into bookends can be found at TheRockShed.com.
Swirls of natural graphic design make a group of agate ornaments intriguing for the holiday tree, or just to hang on cupboards or window latches.
Target's fall collection includes the Threshold agate bookend, sleekly honed on one end to show the swirling layers, and left in its natural state on the other.
Agates have been prized since ancient times and were actually named by the Ancient Greeks after the river Achates where they were first found.
At first, from the 1400s onwards, the cutters in Idar-Oberstein used locally-sourced material found along the Nahe river but when supplies ran out in the 19th century they started importing agates from Brazil and elsewhere.
There are currently over 100 different varieties of agate from Mexico; a number of observable features which are characteristic of the various types of banded agates are key in distinguishing one variety from another.
The agates from this region all originate in what is locally known as the Rancho El Agate andesite, a 38-million-year-old porphyritic andesite.
Agate, formed when mineral-rich water flows through volcanic rock, consists of millions of micrometer-sized crystals.
Observing agate slices with transmission electron microscopy and ion mass spectroscopy, the two scientists found that the size of the tiny crystals and the degree of impurities change cyclically, forming the iris band's crystal pattern.