According to a source, 10K SR means solid 10K gold while SR is the manufacturer's mark.
Some might say that the SR means "silver". However, standard nomenclature or terminology would be .925 or sterling or some percentage, specifying the type of silver or percentage silver, not just silver.
“Karat” is a term that describes the purity level of gold. 10k gold is 41.6% gold, the lowest karat gold that can still be sold as “gold” in the US.
In jewelry news, style queen Katy Perry will be launching her own line of jewelry and accessories, Katy Perry Prism, for Claire's. Find out more here.