For your consideration is a 12.1ct piece of Ready-to-Dop  London Blue Topaz preform.
 
NOTES:
This stone is well shaped with a good symmetry. A skilled cutter should be able to yield an approx. 8-10ct finished gemstone. 
 
*Please refer to the photos/video for color and clarity details.
 
Mineral: London Blue Topaz
Origin: Brazil
Weight: 12.1 ct
Dimensions: 14.5mm x 11mm x 10mm
Clarity: Clean
Treatment: Irradiated