1874-1937 San Francisco Mint Coin Treasury Department

Not much help. Just curious what metal is it made of?

Nice medal!

The Mint began striking these small bronze medals for collectors back in the 1970s. This particular medal is/was part of the Mint's "Official Mint Medals and Historic Buildings" series and is catalogued as number 751 on the Mint's list.

When a portion of the Old San Francisco Mint was re-opened for public visitation in 1973 as a museum, it featured an old coining press on which visitors could strike their own souvenir medal; the same medals were also available over the counter. My understanding is that the medals struck for sale at the Old Mint carried the "S" mint mark.

The Old San Francisco Mint building design seen on the medal's obverse was created by Sherl J Winter, an engraver at the US Mint in Philadelphia; you can see his initials "SJW" just below the building at the far right.

The Old Mint Museum was closed in 1993. From time to time, the Mint has struck additional copies of the medal in Philadelphia; these medals do not have a mintmark. Similar medals have been struck for each of the Mint facilities over the years.

In terms of value, these pieces are not a "hot" area for collectors and so many are sold on ebay and at coin shows/shops for under $10 (often for under $5). Sellers often try to get more (and sometimes do) but a patient buyer can get one for just a few dollars.

Hope that helps!