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COPPER REPLACEMENT AGATE
 
This copper replaement agate is from the Kearsarge Lode. Most of these agate are small, from 5 mm to 25 mm. They are collected because of their rarity,  their amazing details of the native copper replacing fortification bands, and colorful pastel patterns.
This copper replaement agate is from the Kearsarge Lode. Most of these agate are small, from 5 mm to 25 mm. They are collected because of their rarity, their amazing details of the native copper replacing fortification bands, and colorful pastel patterns.
The greens include the copper mineral malachite along with pumpellyite and epidote. The native copper is metallic red-gold.

A Kearsarge Lode copper agate that appears to be a small agate joined to a larger one.
A Kearsarge Lode copper agate that appears to be a small agate joined to a larger one.
The striking feature of this copper agate is the large reddish area on the lower left. You are looking through very clear calcite to the backside of the agate whose inner surface is covered with the reddish copper mineral chalcotrichite. The milky white is chalcedony.
 Kearsarge Lode copper agate typically have fortification patterns with these pinkish-tan hues and small flecks of  copper. The clear area in the lower  center of the agate is  calcite!
 


Copper Replacement Agate cabachon
Copper Replacement Agate cabachon
Many of the larger copper agates are too fractured from the mining process to cut a cabachon. This magnificent one wasn't. The dark inclusion in the upper center appears to be dense plumes of tenorite, the black copper oxide.

The "Easter Egg" in situ in basalt. The basalt has been modified with grainy minerals and  beautiful green feldspar crystals
The "Easter Egg" in situ in basalt. The basalt has been modified with grainy minerals and beautiful green feldspar crystals
The field collector from Hayward, WI gave this copper agate the nickname...the" Easter Egg" because it reminded him of the pattern on decortive easter eggs.
Twenty years before the current copper agate collecting craze in Michigan's Copper Country a local collector found this agate on a poor rock pile near the Wolverine #2 Mine. He swore me to secrecy.
Twenty years before the current copper agate collecting craze in Michigan's Copper Country a local collector found this agate on a poor rock pile near the Wolverine #2 Mine. He swore me to secrecy.
The collector ground away the outer coat and polished it to reveal the intricate copper replacement designs. Today I still have about 20 of these early copper agate.



There's beauty in the details...a close up
There's beauty in the details...a close up
The field of view is about 5 mm x 3 mm. The white fortifications on the lower right are chalcedony. The top third is a mixture of native copper, malachite and tenorite. Arcing downard toward the center is a plum-red crust of chalcotrichite, a red coppr oxide. The black arc just below the plum red crust is clear calcite that enables us to see the rounded hanging mound of native copper. These agates invite more study...join me.
Kearsarge Lode Copper Agate
Kearsarge Lode Copper Agate
With white chalcedony fortification bands on the left and clear calcite on the right, all surrounded in a shell of native copper it's a striking copper agate. What makes it even more striking is we can look through the clear calcite to the inside of the far side of the agate where a mound of green malachite is surrounded by red copper oxide,
Another Kearsarge Lode or Calumet & Hecla mine copper agate
Another Kearsarge Lode or Calumet & Hecla mine copper agate
Notice how the copper replacement of the quartz follows the rounded surface of the chalcedony fortification band. which emphasizes the transparency of the remaining chalcdony. The multi-colored area on the left end of the upper half is filled with a clear calcite.
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