Rock type indentification - Atlas Mountains

[Ao1]

Hi all,

I was in the Atlas mountains and found some rock structures that have puzzled me.

This rock was evident in huge boulders and smaller stones. The pattern went right through the rock. Is it fossils or some other form of inclusion?





This rock was formed from lots of smaller rocks and stones. How is that formed?



Thanks in advance for any help you may be able to provide to help me understand these rocks and how they might have formed.

 

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[stdenis_jd]

It's diabase - mafic intermediate igneous rock. Mafic lava (generally silica-poor), with plagioclase feldspar phenocrysts. The feldspars form first within the melt, then the rest of the rock solidifies and you wind up with those little white "floaters"

 

[ToddsPoint]

I use diabase porphyry for lapidary work. It polishes well and the phenocrysts are attractive. I've rarely seen anyone else use it for anything. Gary

 

[fuss]

You do really nice work Gary.

 

[Ao1]

It's diabase - mafic intermediate igneous rock. Mafic lava (generally silica-poor), with plagioclase feldspar phenocrysts. The feldspars form first within the melt, then the rest of the rock solidifies and you wind up with those little white "floaters"

Thank you for the detailed explanation, much appreciated!