Top 10 Gemstones with a Hexagonal Crystal System
The hexagonal system gives the crystals six sides. Three of these are equal in length and meet at 60° to each other. The C, or vertical axis, is at 90° to the shorter axes.Mineralogists sometimes divide the hexagonal crystal system into two systems based on their external appearance - the hexagonal and the trigonal. But the trigonal crystal system is a subsystem of the hexagonal and most gem references will list the trigonal system as hexagonal.
There were images to these items... Why they suddenly disappeared?
Clearly a Hexagonal Crystal Subsystem. It's visible
Hexagonal subsystem, obviously. It's also visible.
The image shows Red Beryl, which is the rarest color for beryl, but beryl is usually colorless
Its crystals have a Trigonal shape, so it's Trigonal subsystem of the Hexagonal system
It belongs to the Hexagonal subsystem because aquamarine is just blue beryl and all beryls are with Hexagonal shapes
Trigonal subsystem (the image shows black Sapphire but they can occur in all colors except red)
Hexagonal subsystem - because Emerald is actually deep green beryl
Hexagonal subsystem.
Its blue color is awesome (color isn't related to the crystal system though)
Trigonal subsystem (the image shows Green Tourmaline - green is the classic color of the gem, but they can be different colors)
Hexagonal subsystem because it's pink beryl
Trigonal subsystem (amethyst is a semi-precious variety of quartz )
One of the rarest gems in the world
Another extremely rare gem first found in Quebec, Canada