A small vintage, or most likely antique, natural oil stone or razor hone in a bespoke hardwood box.

This stone measures approximately 3³/₈ inches (86mm) by ¹³/₁₆" (20mm) overall.

The top surface is slightly dished from use.

There is a hollow or well in the lower wooden box section at one end and this appears to be intended rather than through wear as the lid cut out fits snuggly over the stone.  Possibly used to hold liquid lubricant during use?

The mahogany (?) box measures 5⁷/₁₆ by 1¹³/₁₆ by 3³/₈ inches tall (138 x 47 x 86mm), previous owner's stamp 'N SHERMER' to each end.