Dumortierite

Dumortierite opens the doors of insight, activating the third eye chakra and assisting one in making the mental leaps necessary for transcending difficulties and solving problems. It promotes self-discipline, especially in regard to learning new things.
Dumortierite is particularly beneficial for students who are required to consume large amounts of information in short periods of time as it enhances all mental abilities. Dumortierite is also a very spiritual stone, activating psychic abilities and stimulating clairvoyance. 
 
Approximate weight of each piece
A 10g
B 10g
C 5g
D 4g
E 7g
F 4g
G 4g
H 4g
I 3g