Featured Edwardian Opal Platinum Ring with unknown H hallmark

I am hoping someone here might know or be able to point me to a resource that would help identify the maker of this platinum opal ring. The hallmark is an H in a diamond-shaped frame. (The markings to the right of the hallmark are hand-etched and believed to be property inventory markings.)

There were a couple of links in my Google search that looked promising but sadly provide no answers.

 

that casting looks a little rough for such a fine metal...........??

has it been tested by a jeweller ?

 

@komokwa, yes. I think the image appearance is more an issue of it being enlarged. (I'd cropped it too small, to 700 pixels, then enlarged it.) Thanks for asking as I'm sure it's likely others would process it in the same way. I'll have to take more / better close-up photos of the markings.

 

What is the "V" to the left of platinum and the poorly stamped letters under platinum.

 

It's part of a hand etched marking that I'm fairly certain is an estate inventory / insurance marking.

 

I think the opal might be a replacement. Thats a fancy setting for such a humble stone.