I have a Sterling Silver chain that has the markings HCT 925 and Canada on the Lobster Clamp ends. I was under the impression that HCT 925 was Italian made Sterling. What possible reason would there be Canada written next to the HCT 925.
If you had opened the link you wouild have seen that HCT is Harcourt, Inc. They are/were the manufacturer of the necklace. (Out of business according to Trademarkia). In my searches I found some stamped Italy and others Canada, like the OP's. There seems to be a bit of controversy with the ones stamped Italy, but from what I can find on other sites and ebay the ones stamped Canada seem to be fine.
So what the OP has is a sterling silver (925) necklace made by Harcourt, Inc (HCT) in Canada.