Help Identifying Medieval Coin - Three Pronged Cross Trefoil

Sorry about the picture. A better one of the front is below. The back appears to be blank with some wear. Neither side has any writing. I sort of suspect that the design is so basic (a trefoil with three clover or cross shapes inside on prongs radiating from the centre) that it may be hard to identify.

I have found a coin that looks like this.
Found it in : "Silver Pfennigs and Small Silver Coins of Europe in the Middle Ages"
Written by : "David P. Ruckser and Lincon Rodrigues"

Austria
Friedrich the Handsome as king (1314-1330)
Pfennig (Silver)
Mint city: Vienna
Obv: Three cloverleafs joined at stems in 3-arched border, balls in outside angles.
Rev: Embossing traces (Eagle)
Weight: 0,62g
Reference: CNA B219

Thanks very much all. The silver pfennig that Petrus found looks exactly like it. I'm not 100% sure mine is silver but I know nothing about silver coins except that a cleaned silver denarius and 1300s English Edward II silver penny I also bought are lighter in shade (although the 1300s penny is darker where it isn't raised).

Where my pfennig (it really looks like that coin, if that's what it is) has worn away there is a brown metallic colour underneath or growing on it. The first two photos are better at showing the coin's colour, the single photo gives it a yellow hue that it doesn't actually have (I had my bedside lamp on it). Does silver have that brown metallic underneath/growth and can it be darker when not cleaned?