Does anyone know what color this is?

The ladies at the handbag authentication thread might be able to tell you. Or you can take your bag to an H store and ask them, and compare it with the leather swatches if they have them. Or they might even have a new item in the same leather as your bag. Each leather can look a bit different, even in the same color.

My guess, from color as it looks in this picture, is bleu de malte. That color has a hint of a green tone to while abysse, to me, is a true blue with more purple in it. It's darker than malte. Both are lovely!

What is the date stamp on the front strap, the letter inside a box? Bleu de malte first came out in FW 2010 I believe, and 2010's letter is [N]. So I would think that if the letter is [M] or earlier it should not be bleu de malte. But there always seem to be exceptions. Bleu abysse came out before that but I bet they still made it when Malte was being introduced.
 
Pierina offered great advice. I would also guess bleu de malte and I have owned H bags in both colors. Bleu de malte has a hint of green undertone, while blue abysse is darker and closer to navy. It can be difficult to distinguish the difference in photos though.
 
I have a blue abyss too, the one in my avatar, and it does not look like this. Think it is blue de malte too, although my kelly wallet in blue de malte is lighter. But it is a photo so....
 
Thank you all for your comments! I thought it was BdM but the production stamp is for 2009. So maybe it is BdP after all?!?! I didn't know BdM only came into production in the fall of 10. So insightful, you ladies!!! Thanks!!!
 
Thank you, ladies! Mystery is solved. It is Bleu de Prusse!!! I thought BdP was offered from 2010 but looks like it was offered from 08. Bleu de Malte came into production in 2010. So BdP!!!