A 1 öre (klipping)RUOTSI-SVERIGE-SWEDISH copper coin from 1626
with a very very nice dark green patina, Cu 2/1.
Weight 25g (original weigh 28.3g at issue) made at the mint at Sater.
30 x 30 mm
2,5 mm thick
GUSTAV II ADOLF (1611-1632)
The obverse says Gustav Adolf Rex 1626 shown by the three crowns and
the letters A G R. He was king 1611-32. He fell in the battle of Luetzen
in Germany in the 30 Years War.
On the reverse is a crown, and under it two crossed arrows -->. Between and
outside of the arrows and under the crown there is the inscription 1 öre.  
It is called a klipping, meaning its shape of a (German words Klippe Klippes)
coin in square shape. Some were made as emergency money or siege money.  It
is No. 88 in catalogue Harry Glueck and Jan Hyllengren SVENSKA MYNT meaning
Swedish coinage, Stockholm 1977.
The group of coins where this belongs was headed Valsverkspraeglade. 
The word means produced by means of a cylinder press. That was a novel way of
making coins, the engraver worked with a cylinder which when rotating in the
press would produce multiple coins instead of hammer-made coins which are one
at a time.
First a long strip of copper would be cast, in this case about 2.5mm thick and 30mm
wide.  Then the strip would be mounted on the cylinder press and the actual stamping
would occur. After production the strip would be removed and the coins chiseled
out of the strip. The chiseled parts would then be smoothed and the coins would be
finished.  Because of the production process all such cylinder-produced coins
are not flat but dished. It was a good idea that lasted long, but finally replaced.
Going back to the word "Valsverkspraeglade".  The letters on the begin of the word
would indicate vals, or false.  In German the word cylinder is Walze, and in Swedish
vals.  The word for false in German would be falsch, and the Swedish word would be
pronounced the same, but written falsk.
In Krause Mishler for 1600's it is # KM 106.1