THEY LOOK THE SAME,

BUT THEY'RE NOT!

 

 

 

 

The four black, glassy-textured samples shown above look very similar - almost identical.  But, these represent four very different geologic materials, formed by very different processes.

 

At upper left is obsidian (volcanic glass).

At upper right is indochinite (impact splash glass).

At lower left is gilsonite (naturally solidified oil).

At lower right is anthracite (metamorphic coal).

 


 

 

 

These three white powdery specimens look identical.  But, they represent quite different geologic materials & formed under very different conditions.

 

At top is chalk (calcitic biogenic sedimentary rock).

At lower left is diatomite (opaline siliceous biogenic sedimentary rock).

At lower right is kaolinite (massive clay mineral from complete alteration of feldspar).

 


 

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