Roman silver coin? [resuelto]

Hello! I have a question about the composition of this coin. When i look up this coin on this site it says silver but it really looks copper/bronze. Same thing for some other coins i have identified. Thanks in advance for explaining this to a new collector.

You don't have to take a picture of your screen, just copy the link of the page. 🙂

N#291062 

It just states silver no fineness and is likely billon (>50% silver) which can look quite coppery in addition to silveroxide.

alright that is interesting the graph really helps thank you! i assume these later roman denarius and antoninianus are not as saught after as early ones?

They're sought after however they're also much more common making them less valuable and collectors usually seek only high grade coins. The one you have is from the Siscia mint so anyone collecting Siscia like me would be interested in it.

Okay is there a specific mark on the coin that explains its from Siscia or how does it work? 

Usually there's a mark on the reverse or a specific reverse is tied to a single mint. Later coins have the mint initial on the reverse.

Here's a much more detailed explanation with a list of mint marks along with dates of operation: https://www.forumancientcoins.com/numiswiki/view.asp?key=mint%20marks

The XXI on the coin indicates that it is a post-reform Antoninianus (sometimes referred to as Aurelianinus).

It has a XX (20) to I (1) copper/silver content (~5% fineness).

 

I wondered what these numbers mean, so it a 20:1 coin from the first workshop/mint (prima [officina])?

Idolenz

I wondered what these numbers mean, so it a 20:1 coin from the first workshop/mint (prima [officina])?

Indeed 👌

Romans clip coins remelt the clipping add copper and make coins 

That coin look like it never been clipped vary rare