Sterling Silver Ring Marked 900 Hallmark Radiating Star??

[DiamondAnnie]

This ring is engraved 900 with curved lines out each side of the number. The hallmark is smaller than a pin's head stamped on the back of the ring band. It appears to me to be a star with radiating rays, but I could be wrong. Unable to find this mark anywhere. I posted this under German Silver as I believe 900 was used on German Silver. Please advise any information that could help me locate the maker of this piece. I took the ring to a rock shop and to a geologist, neither of whom could identify the type of stone used in this ring. They had never seen a rock like this one. Any help would be much appreciated. Thank you.

[Bahner]

Hello, could be German, though I don't recognize the mark. The stone could be lapislazuli. Best wishes, Bahner

[kerangoumar]

The stone is not lapis, it is sodalite, which is one of three minerals that together most commonly make up lapis. This page will show you a nice representative piece of sodalite rough:

http://www.dkimages.com/discover/previews/973/25006612.JPG

As for the mark, I couldn't make it out. However, until the end of the 19thc when huge amounts of it were discovered in Ontario, Canada, sodalite was relatively uncommon and mostly found in Greenland, so the mark could be Scandinavian.