They are calling this a 19th Century Cavalry Picket Pin ...

[relic nut]

Looks right to me. I googled calvery picket pin and found several that were similar. Check it out
http://www.mcpheetersantiquemilitaria.com/04_horse_equip/04_item_066.htm
HH RN

 

[Mud Hut]

THANKS! I certainly appreciate the efforts.