This is a Beautiful Large Gemstone Black and White Buffalo Stone .925 Sterling Silver Statement Ring. 

In Shades of Black and White, with a Sterling Silver Framed Edge.
The Domed Oval Shaped Stone Measures 1 1/4" Top to Bottom, 7/8" Wide, Including the Setting. 
Marked 925
Size 7
11.1 Grams Total Weight.
Gift Boxed.

The trade name of “White Buffalo” is used to identify the stone from the 
Tonopah, Nevada mine owned by the Otteson family.
The main mineral in white buffalo stone is Calcite. 
But depending on the crystalline structure of the Calcite, 
it morphs into minerals called Dolomite or Aragonite.
This healing Chakra Stone will console you and purify your energy. 
This white rock with dark cracks is considered a strengthening stone one 
of the most powerful in the metaphysical gemstone family.