Crystallologists have determined that there are seven crystalline systems, of which 32 are branched...

• The cubic system is like fluorite diamonds, spinel, pyrite

• The hexagonal system ... such as quartz..beryl emerald

• A rhombus system ... such as a sulfur crystal

• Quadruple system ... like zircon ... Edo Kraz

• The straight rhomboid system, such as olivine, topaz, aquamarine, hematite, erguanite...

• Monoclinic system ... Brazilians ... azurite ... the ship ... spodumene.

• Tri-tilt system, such as corundum, sianite, rhodonite

Gemstone crystals grow in a specific geometrical system but sometimes grow nested or joined together

And it grows in an irregular, deformed shape ... according to the reservoir and the pressure it is exposed to if the medium in which it grows without obstruction
Sometimes they grow in clusters according to the shape of the void in which they grow.
Sometimes a limonite takes the form of a pyrite crystal with a grooved cubic, this phenomenon is called pseudo-formation
There are amorphous gemstones such as..
Amber ... and chrysocolla, which resembles turquoise stone ... obsidian, volcanic rock glass ... and opal...

Some forms of crystal systems:

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