Hi, the signature reads "Legras", not Ingres. What you have is a French miniature painting, likely after a bigger painting,and I guess it is painted on Ivory. Date should be early 20th century. The quality is quite good. When you search for "Legras miniature portrait", you will find comparable ones. There is one on ebay labeled as "ox bone" right now, but IMO the price is too high, at least for where I live... And, depending on where you live, have in mind that it is not allowed to sell ivory in some places...