About Heritage Auctions - Coins: US

David Mayfield is a Vice President at Heritage Auctions. David started collecting coins at the age of nine and has been trading at coin shows since he was ten years old. David became a full time coin dealer in the early 80's, and has been a regular on the national and international coin show circuit ever since. David came to work at Heritage Auctions in 1992, and since has had the pleasure of assisting thousands of collectors in building their collections and ultimately in helping them bring their collectible legacy to market. David oversees Heritage Auction's numismatic consignment division, and works with collectors and Consignment Directors across all of Heritage Auction's collectible categories.

Sarah Miller is Senior Vice President and Partner at Heritage’s New York Office and brings a lifelong passion for coins. A student of numismatics since age 11, she first fell in love with coins and their history while attending her first coin show. This led to a job in rare coins throughout high school and college, where she graduated Summa Cum Laude from North Central College in Naperville, Ill., with a degree in Finance and Economics.

Sarah assists Heritage clients with buying and selling their rare coin and currency collections on a daily basis. She has twice appeared as a numismatic expert on CNN and is a current member of the Professional Numismatists Guild, American Numismatic Association, the American Numismatic Society, and the New York Numismatic Club. She is also a licensed Auctioneer in Texas, Florida, and New York City.

An award-winning professional numismatist, Mark Borckardt has served the hobby full-time since 1980, and is currently a senior numismatist and cataloger with Heritage Auctions, a position he has held since June 2004. His interest in numismatics dates to the mid-1960s, and his experience in the business began part-time attending coin shows to buy and sell material about 1970.   

Borckardt began cataloging rare coins for auctions in 1989, and since that time he has handled 80 of the 100 top United States coins according to the itemization contained in 100 Greatest U.S. Coins by Jeff Garrett and Ron Guth. He is a life member of the American Numismatic Association, Early American Coppers, and the Numismatic Literary Guild, and a member of several other numismatic organizations including the American Numismatic Society, the Chicago Coin Club, the Central States Numismatic Society, the Civil War Token Society, and Florida United Numismatists. Borckardt was nominated and elected to membership in the Rittenhouse Society in 1994.   

With Heritage Auctions, Borckardt has cataloged 28 of the firm’s million-dollar coins. His numismatic experience includes important discoveries such as a new early half dollar variety, 1806 O-130 and rediscovery of the missing George O. Walton specimen of the 1913 Liberty nickel. Borckardt is co-author of Million Dollar Nickels, telling the story of that important numismatic event.  He is the editor of Walter Breen’s Encyclopedia of Early United States Cent, 1793-1814, earning the EAC Literary Award in 2001 and the NLG Book of the Year award that same year. He has also contributed substantially to many other numismatic reference works. In addition, Borckardt has penned many articles for The Numismatist, Penny-Wise, and other numismatic publications.   

Borckardt has contributed substantially to countless numismatic auction catalogs, and served as the sole cataloger for several important catalogs. He has experience with many of the most important collections sold at auction including the Eliasberg Collection, the Harry Bass Collection, multiple collections of Dr. Steven Duckor, the Eugene H. Gardner Collection, the Eric P. Newman Collection, the Donald G. Partrick Collection, and others. The Newman and Partrick Collections included significant offerings of American colonial-era coins.

Awards include the Early American Coppers’ Herbert Silberman Award in 2021, the ANA Numismatist of the Year in 2020, an ANA Presidential Award in 2018, the Numismatic Literary Guild’s Clemy Award in 2016, and several other awards from the Numismatic Literary Guild. Borckardt has also delivered several talks and presentations at various numismatic meetings, and has served multiple times as an instructor at the ANA Summer Seminars.   

George Chua is a Consignment Operations specialist for U.S. Coins and is a collector of rare stamps. He started collecting during overseas trips as a child to the Far East and his interest developed into a lifelong passion and pursuit of philatelic knowledge. He has been a member of the American Philatelic Society since 1988. George’s experience with stamps allows him to work closely with collectors to assist in the evaluation and management their collections.

Marc Emory was born in northern Virginia, where he grew up the son of a Washington D.C. newspaper correspondent. As a child of the Washington political scene, he visited the White House at age 13 and Capitol Hill many times. Like many children of Washington, he attended the Sidwell Friends School. He was then accepted for the School Year Abroad program in Barcelona. He then went on to graduate from Andover (1970) and, four years later, graduated cum laude from the University of Pennsylvania (1974) with a degree in Spanish. He has always had an interest in languages, and while at Penn, he was introduced to German and Swedish and continued his studies in Spanish and Russian from high school. In addition to those four languages plus Catalan, a byproduct of his year in Barcelona, he has since learned French, Italian, and Dutch. Always interested in collectibles, Marc was impressed from early childhood by the Smithsonian collections of both coins and minerals, which were within walking distance of his father's office at the National Press Building at 14th and F streets in Washington, D.C. He maintains an extensive collection of minerals at his German home near the Rheinland city of Dusseldorf, which he shares with his wife, Elisabeth, of 43 years. 

Marc also has a collection of U.S. and world coins and an assortment of guitars hand-crafted by legendary luthier Bozo Podunavac. A musician by hobby, he has made recordings and done solo concert tours in his spare time. He has performed before Presidents Ford and Clinton. Marc has been with the Heritage organization without interruption for over fifty years, the first seven with one of the firms that later merged to form Heritage.After graduating from the University of Pennsylvania, Marc founded and oversees the operations of the Heritage Overseas offices, which are now in France (since 1979), Germany (since 1979), Switzerland (since 1984), and the Netherlands (since 1990). The European offices, under Marc's supervision, offer Heritage services to collectors, consignors, and estates in their own countries and languages, as well as to banks and Central Banks around Europe and the world.

Al Pinkall joined Heritage as Director of the Numismatic Sales Department in 2011. A collector since childhood, Pinkall has been a full-time professional coin dealer for 25 years with extensive experience in high-grade and proof classic U.S. coins. In 2010, he acquired the rare coin and precious metal assets of another New England dealership, Ed Lee Certified Coins.  

Pinkall’s business success has been built upon the foundation of providing the most candid, expert, and ethical advice to collector-investors who were acquiring expensive numismatic rarities. His stellar reputation in the high-end numismatic community, providing such high levels of service and expertise, has made him a natural fit at Heritage.

Teresita Ramirez grew up in Texas and attended the University of North Texas before joining Heritage Auctions in 2008. She began her career with Legacy Client Services and advanced through several roles, developing a deep expertise in client relations and consignment management.

Her dedication and passion for the industry led her to her current position as Dealer Consignment Coordinator. In this role, she works closely with dealers to manage consignments and ensure a seamless auction experience.

Teresita loves to travel and attend national coin shows, where she combines her appreciation for history with her love of connecting with people. Outside of work, she enjoys spending time with family, relaxing with her two corgis, and discovering new restaurants and local art events.