Sarah Coventry

In the mid-1980s a subsidiary of Playboy Enterprises. Inc (the publishers of Playboy magazine) owned the company, as it was planning on diversifying into a brand management company. It later sold the company in the 90's; Sarah Coventry jewelry was purchased at home jewelry parties by "fashion directors" throughout the country. However, Sarah Coventry jewelry was re-opened years later by new owners and was. being distributed by representatives via catalogs, the Internet, home shopping networks, and other means. The company has since gone out of business.

Some marks seen on vintage jewelry include:

There is usually but not always a copyright symbol accompanying the mark.

...
Wikipedia