Jewelry, Gems, & Minerals/stamp on ring


I have a small ring that is stamped 14k-18k MDCO. Can you tell me anything about those stamps? The ring is yellow with hearts across the top that appear to be a silver color.

Jason, thanks for the question.

Your description of the ring gave me the clues needed to answer you.  By Federal regulations, if a piece of jewelry is made or more than one quality of precious metal, the stamping must reflect that fact.  For instance, if silver and 18k gold as in some of the designer silver jewelry with gold acents, the mark includes both silver and 18k.  In your ring, it is most likely the hearts are 18k white gold and the body of the ring is 14k yellow gold.  Accents are generally the place a different color or quality of metal is used.

There is not a requirement to mark jewelry in the first place but it would not make sense to leave off the mark and create doubt in the customer as to what is the metal. However, when the metal is stamped, law requires the maker to place their mark near the quality marek. This is like signing to the validity of the metal markings.  In this case, the marking MDCO is surely the makers mark.

Jason, there you have it. Thanks for asking. Enjoy knowing what the ring is now.
God Bless and Peace.  Thomas.

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Have a question about jewelry repair or working with precious metal jewelry and gemstones? For many years up to December 31, 2010, I was a working professional bench jeweler, involved everyday with setting stones in mountings, designing and making jewelry, repairing and limited custom manufacture. If you work with jewelry as a hobby or as a profession, I might be able to help. I deal with the retail business, not mass production. Ask privately if you wish. See the box for that: It keeps your question between us. Please DO NOT ask MAKER'S MARKS, but metal quality marks are fine to ask. Please DO NOT ask diamond prices. See a gemologist for that.


I have extensive experience in design, service and making of jewelry. I deal mostly with precious metals and gemstones but work with many materials as needed and usable to create an artistic design. My experience also includes freelance photography and photographer of jewelry and similar items for a former employer and individuals. Design of custom items requires reading the desires of the client and being clear on what can be done within that framework...then fulfilling the transition of idea to reality. Effective communications is essential in a working designer/producer and customer relationship.

Education is English/Physics! Started in human resources, to advertising, to, what a road. I have had formal training in jewelry work and many shared experiences with top grade jewelers. We just never know were we will go or be. Follow your best, your dreams, with some discretion! Don't let the work tear up your body along the way as it has mine.

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