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Pseudomorphs -not everything is as it seems

Let the rocks tell their story

When salty ocean water evaporates the salt forms cubic shaped crystals.

natural salt crystals

A quartz rich solution has coated and replaced the salt (halite) crystals with quartz (silicon dioxide)
So the crystal shape is that of salt but the crystals themselves are composed of quartz.
This is called a "pseudomorph" :Pseudo" meaning false and "morph" meaning shape.
The quartz is in the "false shape" of salt.

quartz pseudomorph after halite (salt