DarthYoda333 said:
> any ideas on age?
Your find is indeed (as ARC said) a horse-harness buckle. The specific version you found is called a Conway buckle, named for its inventor. It shows up in very-early-1900s harness-&-saddlery mailorder catalogs, notably the JM Eilers Co. 1907 catalog. Conway buckles are only found as "cross-chronological site contamination" at civil war sites, because they weren't invented until long after that war ended. The Conway buckle performs its function so well it is still being manufactured today. For proof of ID, simply do a websearch for "Conway buckle." See the photos of modern-made ones below.