20 lire Mussolini

I have a coin like this one: http://www.ebay.co.uk/itm/ITALY-BENITO-MUSSOLINI-WITH-HELMET-WORLD-WAR-II-20-L-1928-CENTO-ANNI-DA-PECORA-/290939990384?pt=US_World_Coins&hash=item43bd5ff170.
Now...the question. The color is the same, but with silvery appearance near the rim.
What material is made of?? Diameter is 35.5 mm
I've calculated density and it showed out iron or other alloys.
But the coin is not magnetic.
What can it be?

The Itallian ones are normally stainless steel aren't they?

This is not a coin really, more likely a fantasy.  

Perhaps this can help

http://www.coincommunity.com/forum/topic.asp?TOPIC_ID=97243

I saw that but my coin has a weight of around 15 grams.
And it's brown in color.

Don't know for sure but from the colour I'd say that aluminium bronze is a possibility.

Hello here is the valuable original https://en.numista.com/catalogue/pieces16857.html
There were plenty of Fantasy coins made based on this model with different metals (Brass, Iron, Silver...) sizes and variations.
Here are two that I could find on the Numista library:
https://en.numista.com/catalogue/pieces42165.html
https://en.numista.com/catalogue/pieces5491.html

I've seen some explanation that the reported silver coins are actually silver plated, and the coin core looks brown yellow like mine.  

Maybe a gold plated replica like this...

http://www.ioffer.com/i/italy-1928-gold-100-lire-mussolini-replica-coin-107494827?source=eisi