What app has gray diamond notifications?

[MICHAEL G DONNICI]

Can someone tell me shat app has a gray filled in diamond at its message notification? I do not have a pic of the notification icon as it was not on my phone. It does not look like a diamond as in jewelry but like a diamond on a playing card

 

[Brian706]

Considering that we don't even have a screenshot to work with, I think it would probably be easiest just to ask the person who's phone you saw it on.

 

[mikedt]

Can someone tell me shat app has a gray filled in diamond at its message notification? I do not have a pic of the notification icon as it was not on my phone. It does not look like a diamond as in jewelry but like a diamond on a playing card

Maybe it is a poker app or something?