Idiomorph
Idiomorph (from Greek ídios "own", morphé "shape") is a name for a mineral that has fully developed its own shape. This means that it has well-defined crystal faces and a characteristic geometry. The natural shape of a mineral depends directly on its crystallographic structure. Idiomorphic minerals are formed when they are not spatially restricted in their growth. Examples include fissure minerals that grow in cavities in the rock, or minerals that crystallize early from a rock melt ( magma ) ( Einsprenglinge involcanic rocks ).
The opposite of idiomorph is xenomorph (alien). Only partially self-formed minerals are referred to as hypidiomorphic .
Pyrite cubes (idiomorphic) in the host rock
Idiomorphic quartz crystals
Pseudo- leucite from Brazil
Idiomorphic diamond crystal
Idiomorphic apatite crystals on feldspar
Sharply demarcated idiomorphic insects in an igneous rock (thin section)
In contrast: Xenomorphic quartz (gray) in a rock next to feldspar (white) and mafic minerals (black)
