Fossilized Comb

Discussion in 'General Discussion' started by blueblood, Aug 30, 2012.

  1. blueblood

    blueblood New Member

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    My 9-year old brought home a piece of fozzilized comb from school. One of her classmates found it and thought I would be interested in seeing it. It's pretty cool!! I wanted to share it with you all. I guess it's a piece of honeycomb. Not really sure. I like how it's half geode too.

    IMG_20120830_160526.jpg IMG_20120830_160540.jpg IMG_20120830_160558.jpg IMG_20120830_160606.jpg
     
  2. Noronajo

    Noronajo New Member

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    I've read somewhere that it's a type of coral but looks just like honeycomb to me-beautiful!
     

  3. blueblood

    blueblood New Member

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  4. efmesch

    efmesch Active Member

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    [h=3]I Googled this from this url: http://www.quartzpage.de/gro_text.html. There's a lot more there but the bottom line seems to be that it isn't a fossil but a rare crystal form.

    Honeycomb Quartz[/h]The name "honeycomb quartz" is not an officially approved name, it is made up by me for the lack of an appropriate label. This growth form is so bizarre that I just had to come up with a name. The crystals are hollow, their tips are absent, instead there is a central tube that runs roughly parallel to their c-axis, so the crystals look like a six-sided cup or a honeycomb. Sometimes it looks as if platy, parallel-grown crystals of approximately same size are attached to each other to form a six-sided ring or hexagon, very similar to honeycombs, other crystals look like hollow scepters. I've so far only seen this at 3 locations, all in volcanic rocks:Opal Hill Mine in the Mule Mountains at Palo Verde, Southern California
    Mopah Range, Turtle Mountain Wilderness, Southern California
    Tillie Hall Peak, Mule Creek, New Mexico

    Mullis and Sigl (1982) describe such hollow quartz crystals and aggregates of these quartzes they found in a trachyte from the west coast of Gran Canaria, Spain. The authors speculate that they form in boiling watery solutions and that the crystals grew around bubbles attached to the crystal tips. This view is supported by the finding of crystals whose tips were completed again and in which the cavity was sealed. Such cavities were found to contain water vapor. It is nevertheless not clear if growth inhibition by vapor bubbles is the general mechanism behind the formation of these and similar crystals: some of the hollow crystals get fairly large and have an internal diameter of one centimeter but are just one centimeter high. It is difficult to see how a small crystal "grows its way around" a large bubble - the fastest growth occurs parallel to the c-axis, so a crystal that encloses a large bubble must already have a diameter that is close to that of the bubble.
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    This specimen is from the Opal Hill Mine at Palo Verde, Imperial County, California. This spot is one of the few fire agate localities (fire agate is presented in the chalcedony subsection), but you can also find chalcedony roses. In the upper half of the specimen you see a small aggregate of six-sided hollow crystals inside such a chalcedony rose.[TABLE="class: pix, width: 265"]
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    A close-up of the honeycomb-like crystal aggregate shown in the previous image. This is the only specimen I have where several hexagons form a structure not unlike a small wasp nest. Note that the crystals outer shape is clearly hexagonal like an ordinary quartz crystal prism, but the internal walls are rounded.

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    This image shows a cavity in a volcanic host rock that is outlined by irregularly intergrown crystals. The larger ones assumed a cup-like shape, like the big one in the center of the image with an internal diameter of about 1 cm. On its left side there is another "cup" in which smaller crystals started to grow from the ground of the cup and form multiple terminations. From Tillie Hall Peak, Mule Creek, Graham County, New Mexico.

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    Two hollow crystals on the specimen shown in the previous image (but not visible on that photo). By a lucky coincidence the right crystal has been split parallel to the c-axis so the hollow tube can be seen framed by the shiny fracture surfaces left and right to it. There is a "plug" in the tube with a small crystal tip on top of it (pixel coordinates 1805,1284, counting from the upper left corner at camera resolution) and another one at its bottom (pixel coordinates 1937,2148). The lower end of the cavity is marked by black dots of an unknown mineral (possibly iron or manganese oxides). The left crystal is mostly intact, only at its base (around the pixel coordinates 1316,2032) there is a little hole and one can look into the cavity. In both cases the cavity reaches the base of the crystals, it is not just a shallow dent, and the diameter of the cavity amounts to about 30-60% of the external diameter of the crystal. Note the peculiar surface pattern on its prism faces, resulting from several layers that have been deposited on the crystal.
     
  5. blueblood

    blueblood New Member

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    Thanks for the intel Ef. Either way, creation never ceases to amaze me....
     
  6. Gypsi

    Gypsi Super Moderator Staff Member

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    I have a piece of that my grandfather found in southwestern Michigan and gave to me. When I get off the internet and am doing something else, I will remember what he called it. It is quite beautiful, maybe 3 inches across, but the openings are too large to be true honey comb. It's not petosky is it? (with the rest of my internet not working I can't go search it.)
    Gypsi