Wormy looking Geode, Nodule or what...and crystal/quartz piece...

[curious kat]

..Found this rock, has interesting outside & inside. So was wondering which to call it?


...and this quartz piece with crystals in it....

 

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[Cariboo5]

Kinda cool pattern on the outside (never seen one like that before)....reminds me of a cross hatch pattern. Inside looks like there may be 3 - 4 different shapes...

In a name game.........I would call it... " Cross Hatch Delight "

 

[DDancer]

I'm going to guess you found these in or near an area with volcanic rocks. The nodule appears to have zeolites on the interior. The crystaly piece is something I have recovered before and is a kind of geode however these types are formed inside pockets in volcanic magma from highly mineralized water. I'm sure there is a proper name for them but never cared to look. They are cool and very fragile. The outer shape is where the crystals formed on the magma pocket and grew inwards. Some specimen's I have recovered were as big as an egg but most were smaller.

 

[curious kat]

Cariboo......that's a good name for it!

DDancer...oh yes, very volcanic area here. Thanks for the information! Still would like to know how the rock gets that "worm" look?

 

[DDancer]

The worm look is most likely from the magma's interface with the mineralized water as it pushed thru cracks in the magma as it cooled. The process creates micro bubbles and occurs along fractures in the volcanic material. The micro bubbles push out creating a rounded effect along the cracks. To test this you can use a microscope or loupe and in the sharp broken edges of the nodule look at where the solid structure interfaces with the wormy cracks.
Zeolites, silicates *quartz*, sulfides and air pockets will cause similar patterning. Chalcedony *an opal like silicate* is probalbly also present in the area and will create a similar wormy appearance. Look up Chalcedony Desert Rose and see what it looks like... most forms of it look like melted wax and some forms hold value as Fire Agate.

 

[curious kat]

Thank you DDancer for all of the information, can't wait to get out my loop & check it out again. We do have a lot of Chalcedony, the roses and some fire agate as well...I've got quite a few posts on it, think I made people sick of it!

 

[Tigger]

"Awesome" was my first thought, but you want something more scientific - looks like a thunderegg? I've found ones that were conjoined like that, and it has the chalcedony in it. Google thunderegg/ thunder egg images to compare. Awesome exterior though - very nice display sample.
Tigger

 

[stefen]

The worm look is most likely from the magma's interface with the mineralized water as it pushed thru cracks in the magma as it cooled. The process creates micro bubbles and occurs along fractures in the volcanic material. The micro bubbles push out creating a rounded effect along the cracks. To test this you can use a microscope or loupe and in the sharp broken edges of the nodule look at where the solid structure interfaces with the wormy cracks.
Zeolites, silicates *quartz*, sulfides and air pockets will cause similar patterning. Chalcedony *an opal like silicate* is probalbly also present in the area and will create a similar wormy appearance. Look up Chalcedony Desert Rose and see what it looks like... most forms of it look like melted wax and some forms hold value as Fire Agate.

Desert rose was my first thought...one with the pedals knocked off...