Crystal Quartz Round

Crystal Quartz Round
Quartz rock – geode / nodule crystal formations in small pockets, causes / what is this called?

I was rockhounding in northern Virginia last week, at some shale deposits of Quantico near the Interstate, and found some interesting quartz rocks in the shale deposits. More than one quartz rock is exhibiting hexagonal crystal formations in small pockets in the rock, several rocks have multiple small pockets with crystal growth. I know a Geode is a hollow round rock with quartz growing inside, and a Nodule is a fully solid rock with crystalized formations, but what is a quartz rock that has void pockets with small formed crystals inside the pockets? I’d suspect that the quartz didn’t compact uniformly, and had small pockets which contained gas or whatever that allowed the crystal formations later. Some of the quartz on the outside of the rock looks like it was “splattered” on , like adding additional substance after the previous material has hardened, and different colors, yellows, whites, etc. Interesting structure, to say the least. Any theories or names for this structuring?

Vugs are the cavities, and are pretty much geodes still in their matrix.

It sounds like you are describing the drusy crystal habit quartz often displays in shales and sandstones that have had hydrothermic perculation at some point.

Crystal Quartz Round
Crystal Quartz Round
Crystal Quartz Round

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