Certified tanzanite from an accredited lab verifiable online through the app or direct contact via phone number or email.  All photos taken with apple iphone iMax pro on normal setting.  Video and photos match the stone accurately and equally.  Beautifully cut tanzanite round.   Rounds are more rarely seen in tanzanite because the crystal shape lends itself more towards rectangular cushion or oval cuts.   The cutting of a round produces more waste so they are harder to fine but more sought after.   This one has no window which you will commonly see in tanzanites.   Window is where the stones cutting quality is not regarded as highly as the total carats of the final cut stone so you'll see through the middle of the stone and it will not be reflective through the table.   Stones cut for weight over gem quality should be heavily discounted compared to a master cut stone such as this.
Please be aware when shopping for stones if they have window or not.   If you are bargain hunting, a window cut stone could be the right choice for you but please do not pay gem prices for window cutting.   
Stone is 99.999% loupe clean.