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Lake Superior Agate Cabochons
The Lake Superior agate is noted for 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 1 cm in
diameter. A few Lake Superior agates have been found that are 22 cm in diameter with a mass exceeding 10 kilograms. Very large
agates are extremely rare. A 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 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.
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Beautiful carnelian that I collected in the Keewenaw Peninsula last summer. There's some great patterning in this
stone that didn't come out in the photo, but I'll try to take another with the light shining through the gem. Approx.
size: 12x15 Weight: 3.9 cts.
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The patterning came out a little better on this cab in this photo, but still leaves much to be desired. Approx.
size: 12x17 Weight: 4.15 cts.
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Although it sin't a true cabochon, this gemstone has great red and white striping. Shaped kind of like a guitar
pick and flat on both sides, it would make a great piece for wirewrapping or electroforming. Approx. size: 16x22
Weight: 10.7 cts.
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This is a magnificent gemstone of this classic material from the Keweenaw Peninsula in Michigan. There are
great banded patterns in this orangish-red translucent cabochon. Approx. size: 16x24 Weight: 12.25 cts.
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This cab is made up of creamsicle colors and has a big eye-shaped spot dominating it. The sides are a bit
straight on this gem and it might be a little hard to wrap with a bezel, I'm not too sure, but I wanted to warn any potential
silversmiths. I'm pretty sure I could set it though. Otherwise, it would make a wonderful piece for a wirewrap!
Approx. size: 14x23 Weight: 12.3 cts.
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Premium lot of three stunning gemstones perfect for making bewitching rings or petite pendants. Great moneymaking
package! Approx. sizes: 4x6 8x10 8x12 Total weight: 5 cts.
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