Help identify this marker c^a I've found on 2 sterling silver rings

[candeexx]

I've found the same markings on two of the rings I've inherited. They're both sterling silver with the 925 marking but they also both have the following marking that I cannot seem to find info about anywhere online. The marking is: c^a followed by 925. I understand the 925 marking but not the c^a.
Getting a clear and proper picture of them is impossible on my phone but I tried. I can assure you that both markings are the same c^a
I dont know much about jewelry so any info helps! I inherited this from a grandparent who enjoyed collecting a lot of jewelry so I have no idea where it may have come from.
Thanks in advance!

[Juls1969]

CHÂTEAU D'ARGENT

Hallmark(s): "C^A"
Information: Château d'Argent, Inc. was founded in 1993, in Quebec, Canada. Works primarily in silver and gold.