All About Agates!
"Gemstones" are stones which can be cut and polished to be used as a jewel. All of our gemstones are sourced from the Upper Peninsula and are featured in the dreamscape series, rings, pendants, and custom pieces.
Read on to discover more about the Lake Superior Agates we use!
Over a billion years ago, the continent began to shift and lava spewed from the surface. Iron-rich lava flows poured along the fault lines, creating the volcanic rock we find along the north and south shores of Superior today. These volcanic shorelines can be found along the north and west shores of Presque Isle in Marquette. The locals refer to the most dramatic section as "Black Rocks".
As the tectonic plates pulled apart, a large basin was left behind. This basin was baby Lake Superior and in her, agates began to form. Oxygen and carbon dioxide bubbles became trapped within the lava flows forming vesicles.
Time passed and the flows became permeated with groundwater rich with minerals. Quartz crystalized within the gas vesicles and formed the agates we know today.
Agates come in many variations and colors. These gemstones are found around the world, but Lake Superior agates are known for their rich reds, orange and yellow color bands. The coloration is caused by the high concentration in iron oxides in the area.
Pattern variations include fortification agates which feature bold, straight bands wrapping around a center point (below) and the rare eye agates which have perfectly round dot bands that speckle the surface of the stone (above, middle).
Imperfections can become the most interesting elements of stones. In agates, composition variations are known as "inclusions". Plume agates have fluffy inclusions which often appear to be soft and have depth, often resembling feathers, plants, or flowers. These inclusions are created when oxide minerals grow within the forming agate. In the early stages, the agate is a gelatinous substance which provides support for the inclusions to expand. Over time it hardens and the patterns are solidified in the gorgeous gemstones we see today.
Lake Superior agates are the state gemstone of Minnesota. These stones can be found along the shores of Superior, but have also been carried inland by the glacial movements thousands of years ago. To find one yourself, look in exposed gravel near rivers or lake shorelines. The brightly colored bands will often be hidden under a top coat of minerals so other clues will have to be used. Look for translucent parts which indicate chalcedony quartz, the base mineral of agates. Rich red color bands might be visible when the stone is wet. This is often a good indicator of an agate, but the bands can also be pink, yellow, greenish, or even purple. For a more comprehensive guide to agate hunting click here.
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