William Marc Rosenblum, 80, of Littleton, Colorado, passed away on March 10, 2026.

He was born on April 10, 1945, in Orange, New Jersey, to Laura and Carl Rosenblum. The oldest of three boys, Bill grew up in West Orange, where he played ice hockey, delivered newspapers, and developed a life-long appreciation for rock-and-roll.

After graduating from West Orange High School in 1963, Bill headed north to Maine to attend college before landing at the University of Bridgeport in Connecticut. It was there that he met a fair-skinned beauty, the love of his life, Rita Berkowitz. Bill went on to earn his Bachelor of Arts and Science degree in 1971.

Bill and Rita married in 1967 and soon set off on an adventure westward, settling in Northern California near San Francisco and the Russian River Valley during the height of the counterculture era. On a road trip back east, their van broke down in Denver—an unexpected twist that led them to decide to make the Mile High City their home. Colorado remained Bill’s home for the rest of his life. He spent more than 30 years in Conifer and nearly 20 years in Littleton.

An avid sports fan with enough knowledge to fill a stadium, Bill remained loyal to the New York Yankees while also enthusiastically cheering for his adopted hometown teams: the Denver Broncos, Denver Nuggets, Colorado Rockies, and Colorado Avalanche. Above all, he simply loved a good game.

He was also an enthusiastic reader of mystery novels, and always had a stack of new titles within easy reach.

Bill built a distinguished career in numismatics beginning in 1971, becoming one of the field’s most widely respected specialists in the coins and currency of Israel, Palestine, and Jewish numismatic history—from ancient to modern—as well as in coins, paper money, tokens, and medals from around the world. He published more than 250 auction catalogs and price lists, and was an active member of numerous numismatic organizations. Bill was also known for his generosity in sharing his knowledge. A Life Member of the Denver Area World Numismatists club, he rarely missed their monthly meetings. He contributed to many publications in the field, and taught courses for the American Numismatic Association in Colorado Springs. Bill’s contributions enriched the study of numismatics and earned him the admiration of colleagues, collectors, and institutions worldwide.

Bill is survived by his two children: Brian Rosenblum and his wife Eva of Lawrence, Kansas, and Sarah Gumina and her husband Joe of Conifer, Colorado. He is also survived by his brother Andy Rosenblum and four beloved grandchildren: Shimon, Sofia, Rosalita, and TJ.

He was preceded in death by his wife, Rita; his parents, Laura and Carl; and his brother, Peter.

In lieu of flowers, donations may be made in Bill’s memory to:

The United States Holocaust Memorial Museum in support of educational programs

https://ushmm.planmylegacy.or…

The Alzheimer’s Association in support of Alzheimer's research

https://www.alz.org/get-invol…

A Celebration of Life honoring Bill and his wife Rita will be held on Saturday, April 11, at 11:00 a.m. at The Barn at Memorial Park, 26964 North Turkey Creek Road, Evergreen, Colorado. 

Please RSVP at https://forms.gle/BaYjQCBzU98…

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