what is the c-axis on gemstones, can someone explain this axis stuff thx.

[nikkis34]

Like the titles says need help with the axis. thx.

 

[WinkHPD]

In a tourmaline the c-axis is the axis that runs the length of the crystal. In most green tourmaline from Brasil the C-axis is closed, meaning that if you try to look through the length of the crystal it turns black. In a few stones the C-axis is open, meaning you can see down the axis, and this opens up many more cutting styles and oportunities. Most of the red and pink stones have open C-axis.

Wink

 

[mogok]

The "C" axis is is a dichroic or trichoic stone the direction in the stone in which the stone looks like a single refractive (it means that under dicroscope or a polariscope it will show the same reaction as if it was s single refractive stone)
Its usually the main growing axis of many stones like ruby, tourmaline,..
Its the direction in which there is no dichroism, there is no birefringeance,...

Dichrois stone has one optic axis ( called usually "c" axis) trichoic stones have 2...

Thats what I can tell you about...