Just offering this as a possibility and a route for further research:
On Thursday, January 3, 1991, a trademark application was filed for STE G with the United States Patent and Trademark Office. The USPTO has given the STE G trademark a serial number of 74127717. The federal status of this trademark filing is CANCELLED - SECTION 8 as of Friday, February 5, 2016. This trademark is owned by SOCIETE GEORLAND S.A.. The STE G trademark is filed in the Jewelry Products category with the following description: jewelry made from precious metals or coated with precious metals.