Treasure Hunting For Lake Superior Agates

Did you know that the official gemstones of the state of Minnesota are called agates? Of all the beautiful rocks and gemstones that could have been considered, these beautiful stones that are readily available along so many beachfronts of that state are so treasured that they now have that official title. If you're interested in treasure hunting of any type, why not consider treasure hunting for some Lake Superior agates of your own?

These colorful rocks are more than just your garden variety types of stones. They were actually formed literally billions of years ago, when the North American continent began to split because of molten rocks shifting deep beneath the surface of the ground. Water vapor and carbon dioxide became trapped in areas of these lava flows, forming the colorful rocks we now call agates. Their beautiful and unique striped design is what makes them so treasured.

There are two ways to hunt for agates in the Lake Superior area. The first is to scuba dive in Lake Superior for these gemstones. A two hour non-certification class is offered in Copper Harbor and the class covers the location and identification of Lake Superior Agates. Air is furnished for this one tank dive class. Many of the better quality of agates are found on the sand bars in Lake Superior. The water is quite cold and can be very cloudy at times so always use the buddy system when diving.

The second way to hunt for agates is to search the lake shore of Lake Superior and nearby lakes. Hunting for Lake Superior agates isn't as easy as you might think. Their unique banding usually becomes more visible when the rocks are polished and cut a little bit, and not always visible to the naked eye. Prospectors often need to look for other clues when searching for agates. Most have a glossy or waxy appearance and a pitted texture. They also seem to have a glow or translucence on sunny days, usually because of the quartz deposit on the rocks. A brighter day is usually better for hunting than a cloudy one.

The best way to treat agates is by tumbling. This is when the rocks are put into a large vat with polishing grit and tumbled for several days until they are shiny and smooth. Usually areas where you can find Lake Superior agates have places that will do this for you, for a small fee. They may also have many specimens available that have been found by others and that you can purchase for your own. The larger ones are cut with diamond slabs until they're shiny and then are set in pieces of jewelry, belt buckles, and so on.

You don't need to be in Minnesota to find Lake Superior agates. Any waters that empty into Lake Superior will have deposits along the banks of their rivers and streams; up and down the Mississippi River is a great hunting ground for Lake Superior agates. Hikers, campers, and just casual beach goers have found a wealth of beautiful gemstones in many of these areas.

Treasure hunting takes on all forms these days; you can look for coins, shipwrecks, and even valuable rocks and gemstones. For a great vacation activity, why not try hunting for Lake Superior agates? They make great souvenirs for anyone.

Happy Treasure Hunting.

David Cowley has created numerous articles on Treasure Hunting. He has also created a Web Site dedicated to Treasure Hunting. Visit Treasure Hunting.

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How to Find Lake Superior Agates

You have decided to hunt for Lake Superior agates, but how do you know what to look for? There is no simple answer. Usually, the richly colored banding pattern is not well exposed and prospectors must look for other clues to the presence of agates.

The following characteristics will help you identify agates in the field

Band planes along which the agate has broken are sometimes visible, giving the rock a peeled texture. It appears as though the bands were partially peeled off like a banana skin. Iron-oxide staining is found on nearly all agates to some degree, and generally covers much of the rock. Such staining can be many different colors, but the most common are shades of rust-red and yellow. Translucence is an optical feature produced by chalcedony quartz, the principal constituent of agates. The quartz allows light to penetrate, producing a glow. Sunny days are best for observing translucence. A glossy, waxy appearance, especially on a chipped or broken surface, is another clue. A pitted texture often covers the rock surface. The pits are the result of knobs or projections from an initial layer of softer mineral matter deposited on the wall of the cavity in which the agate formed. Later, when the quartz that formed the agate was deposited in the cavity, these projections left impressions on the exterior.

Photo credit mandj98

The Lake Superior Agate

The Lake Superior agate differs from other agates found around the world in its rich red, orange, and yellow coloring. This color scheme is caused by the oxidation of iron. Iron leached from rocks provided the pigment that gives the gemstone its beautiful array of color. The concentration of iron and the amount of oxidation determine the color within or between an agate's bands.

The gemstone comes in various sizes. The gas pockets in which the agates formed were primarily small, about the size of a pea. A few Lake Superior agates weigh more than 20 pounds, about the size of a bowling ball. Such giant agates are extremely rare, but no doubt others are yet to be discovered.

The most common type of Lake Superior agate is the fortification agate with its eye-catching banding patterns. Each band, when traced around an exposed pattern or "face," connects with itself like the walls of a fort, hence the name fortification agate.

A common subtype of the fortification agate is the parallel-banded, onyx-fortification or water-level agate. Perfectly straight, parallel bands occur over all or part of these stones. The straight bands were produced by puddles of quartz-rich solutions that crystallized inside the gas pocket under very low fluid pressure. The parallel nature of the bands also indicates the agate's position inside the lava flow.

Probably the most popular Lake Superior agate is also one of the rarest. The highly treasured eye agate has perfectly round bands or "eyes" dotting the surface of the stone.

Occasionally, collectors find a gemstone with an almost perfectly smooth natural surface. These rare agates are believed to have spent a long time tumbling back and forth in the waves along some long-vanished, wave-battered rocky beach. They are called, appropriately enough, "waterwashed" agates.

Finally, the rarest Lake Superior agate is the one that recurs in a collector's dreams but is discovered in reality perhaps once in a lifetime. On average only one out of every 10,000 agates fits this description. They are the ones weighing 2 pounds or more and having perfect shape, color, and banding quality. They are the ones called "all-timers."

Above is written by Scott F. Wolter and Reprinted with the author's permission. His books "The Lake Superior Agate - Third Edition" & "The Lake Superior Agate - One Man's Journey" are must own books for anyone who hunts, collects or simply appreciates Lake Superior agates.

Buy this great book today! A must own for any collector. . .
The Lake Superior Agate, One Man's Journey

Photo credit Captain Tenneal