Authenticity guaranteed.
Very nice antique russian / caucasian kinjal dagger.  
Circa 19th century.
High quality hand forged multy-fullered sharp blade with maker's marks.
Fancy silver rivets cups on hilt and silver fittings on scabbard. 
Arabic calligraphy on the back of top silver fitting is done with "niello" technique (type of black enamel). 
Grip is carved from one single piece of b0ne.
Domestic cattle b0ne (mentioned to comply with ebay policy). 
Cattle is a large domestic farm animal kept for their milk or meat. This animal is not threatened or endangered or protected by cites, the endangered species act, or any other state, federal, or international laws. It is legal to sell this item and this listing follows ebay rules.
Leather over wood scabbard (sheath).
   large size:
About 21 5/8 in. (55 cm) long in scabbard.   
About 20 1/2 in. (52.1 cm) long out of scabbard.
Blade is about 16 1/16 in. (40.8 cm) long and 1 3/16 in. (3 cm) wide at widest point.
  condition: 
Very good original antique condition with honest wear and charming indication of age. 
Expected stable age cracks, handling marks and age patina to b0ne grip.  
Cleaned blade is in excellent antique condition with minor age wear.
Leather on scabbard shows expected age wear, probably was replaced long ago. 
Fine quality antique example.