Wednesday, August 24, 2011

Natural Wonders: Dendritic Agate

When is an agate not an agate? When it's dendritic agate. These beautiful landscape-like stones are technically a form of chalcedony. Like a carnelian, but translucent. Most agates have some sort of banding that are characteristic of the stone, but dendritic and moss agate, for example, though they bear the "agate" moniker, are a different breed entirely.

The "dendritic" part of the name comes from the dendrites within the host stone, often looking like trees, shrubs, and branches Though these look like plants, they are actually manganese and iron trails that form within the stone. Rust trails, in essence. Which make some gorgeous patterns:

All the dark spots are the manganese and iron trails. This stone really shows the translucency of the chalcedony (the top part that looks so blue is very translucent - you can almost see into the stone, but not quite).

Here's another:

This cabachon is amazing! Brett is from Colorado and he just loves the dendrite stones. He says they remind him of snowy mountaintops. And I think this one shows that effect perfectly.

One more:

I love this too. It's got a bit more of a graphic look, with the white flecked part at the bottom giving an almost 3-D effect. It's as if the top part of the stone is being cradled by the bottom part. Pretty cool, eh?

Dendritic agate can be difficult to cut from the rough slabs, because the dendrites within the stone are not always at the same depth. So some of the visual effects can be lost if the cutter doesn't know how to cut the rough.

Though popular, dendritic agate is found in many locales and can be purchased fairly inexpensively. The trick is finding the right stone shape and patterning. When I find these at a stone seller's table, I tend to spend a long time sorting through all of their cabochons looking for the ones I really consider spectacular. No two are ever alike, and I always want to choose the ones with the best visual effects.  :)

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