Basically the title. A card that to my knowledge has not sold publicly in a decade, perhaps 15 years is available to me. The owner has no idea what the value is and neither do I but we know it's significant. What do you do in this situation? This would be a major major grail card.
[Edit/Additional Info] Other posters asked I share more information so I'm just going to tell you the card to get the help I need. It's the 2001 Topps Chrome Barry Bonds Originals Refractor which hand numbered to 10 on the back. Pics below. Most people have no clue what this card is. Don't even know it exists. One part of me is like, ok it's a rare jersey card with no sig which isn't crazy. The other part of me is like, Oh my word, this is the greatest Bonds jersey card ever, nothing else matters when it stands in the shadow of this card. Pics below. Thoughts?