Mark Guerin co-owns Harris Jewelers in Rio Rancho, New Mexico, with his partner in business and in life, Karen. He attended the Texas Institute of Jewelry Technology at Paris Junior College, where he learned all categories of jewelry repair and manufacturing. Mark attended the Albuquerque School of Watchmaking, earning the title of Watch Technician. He has also completed GIA's extensive Diamonds and Diamond Grading courses.

Mark is a Registered Jeweler with the American Gem Society and has won numerous awards for collaboration and creation of custom jewelry designs with the "All that Glitters" competition, sponsored by the New Mexico Jewelers Association. He currently serves as a Board Member with the Rio Rancho Regional Chamber of Commerce. Mark served on the board of the NMJA, also as an officer, and is a past President of both the New Mexico Jewelers Association and the New Mexico Watchmakers Association.