Dumortierite - Darker in Color

Dumortierite
Assists in communication with angelic or spirit guides
A stone of the mind
Strengthens mental acuity and memory, especially in areas related to math and language
Promotes confidence and a positive attitude toward life
By sharpening focus and acuity, can help strip self doubt and heighten one's ability to stand up for one's self
From Mozambique
 
Please note:  These are priced by weight and not necessarily by size.  They are a beautiful deep blue color, which I was unable to capture in the photos I'd hoped.