Help! Corner chipped in transport, useable?

[newby54321]

Just getting into the hobby, brought a beautiful second hand 300 litre aquarium.
When transported the corner was chipped off, front of the tank. The silicon layer in the tank Is intact and it holds water as far as I can tell. Is this usable or reparable?
Thanks all!

 

[Harpo]

Sorry, but I would not use that. Too risky