1900-S German Coin Pins (1913)

I like it.
John1

P.S. I added the date to your title.

In most cases, neither.

These items were generally produced by someone taking a coin from circulation, bringing it to a jeweller, and paying the jeweller to turn it into a brooch or pendant. The jeweller would then have crafted the mounting to fit the coin.

Most countries, including I am sure early 20th century Germany, have laws in place preventing the deliberate defacement of coins in this way. Such laws may not stop an over-zealous individual from commissioning such items, but would prevent a business from mass-producing and mass-marketing them.

In doing a bit of searching, I found an identical brooch with different coin (1888) on ebay.
https://www.ebay.com/itm/285313982172
I knew the coins could be removed fairly simply with little or no damage to the coins. The brooch itself seems to be specific to the 2 Mark coins.
I also found a 1913 3 Mark commemorative coin in a silver pendant that looks a lot more custom (also on ebay.)
These coins were works of art made out of silver, so they do work well as jewelry. I even have an 1868
3 pfennig coin cut out and a ring soldered to it to make it a pendant. It's nice.