Unknown hallmark on estate ring

[Oceanpixie]

Hi there, I just recently got the ring at an estate sale. I suspect it is platinum. The heft seems right and the metal color looks right. The hallmark looks worn and what is left is "00". There is also another stamp of 053 next to the "00". Anyone come across this before? Thank You for any help!

 

[HopeDream]

Hi Oceanpixie,
Could you post a picture of the mark? It might be 900 platinum.