Hi thanks for your question and yes, I can see why you are confused. The purity degree you would usually see is in an OVAL (on silver) from Italy and usually 800 or 925.
The 750 Italian gold mark for 18 k will appear in a cut off diamond shape not an oval.
Being that the Italian ring is the color of silver, it probably IS silver, unless rhodium plated but doubt it. Most likely 750 parts refined silver and approximately 250 parts base metal. Containing less silver than .925 Silver.
Only objects marked 925 meet the requirement to be termed - "sterling".
Your local jeweler can acid test to positively identify the metal.
85 AR - 85 is identification number of the silversmith and AR signifies the initial of the Italian province.
