I got these and both are different. One gives off a creamy looking swarf and the other grey. One has been used and is worn in the center. Both are hard and smooth. The swarf is from using a diamond 325 on them.
http://i43.tinypic.com/2dvmxhd.jpg
Mostly dry
http://i42.tinypic.com/1piees.jpg
Swarf
http://i41.tinypic.com/wvzi52.jpg
Wet
http://i44.tinypic.com/8zqm4y.jpg
Any ideas?