Is Sodium,Calcium,magnesium,Aluminium Silicate with formula :
NaCa2(Mg,Fe2+)4Al(Si6Al2)O22(OH)2 and hardness 5-6.
Normally occur in green color,but has been also found in pale yellow like this gems here.
Is a quite rare mineral and best location is Vietnam and Burma,recently also Tanzania.
In this gem are visible some small inclusions and the color is a yellow-green.