Forum:Did Snape know the ring was a horcrux?

Did Severus Snape know the ring was a horcrux when he saved Dumbledore from the curse? The Deathly Hallows book mentions that even Mr. Borgin (co-owner of Borgin & Burke) could recognize a horcrux. So, if Mr. Borgin could recognize an object as horcrux, then I guess there is some magical way to test an object for whether it stores the fragment of somebody's soul. If he could do it, then so could a smart man like Snape who seemed adept at recognizing dark magic objects.

If Snape knew the ring was a horcrux, then he could have deduced that other objects were (e.g. - the diary), and that Ron, Harry, and Hermione were hunting for them. Also, Dumbledore should have know somebody like Snape would soon determine the ring was a horcrux and from there learn the Dark Lord's secrets. Did Dumbledore ever tell Snape, "I'm hunting for horcruxes."?