Spodumene
 
 

The Spodumene-group consists of two monoclinic mineral species: 
Hiddenite (yellowish to greenish)
 
 

and 
Kunzite (blue-violet). The Hardness for these mineral specimens  is  6-7, the chemical composition is  lithium-aluminium-silicate. 

 
 

Due to its brittleness, cutting of spodumeme is very difficult, because both hiddenite and kunzite can bust very easy in this process. 
Both mineral species occur in  the USA, Brazil und Madagascar.