Mike your button is the reverse of a Maria Theresia, Austrian coin, looks like a copy (maybe an actual coin made into a button). Nice find, Mike! Congrats!
More info:
Different varieties with Maria were minted for the Austrian empire:
* Austrian Luxembourg and Liege
* Austrian Netherlands
* Austrian Burgau
* Salzburg Coins
* Austrian Lombardy Coins
One in paticular, the Thaler, was a widely circulated coin. Our "dollar" is a word derived from the name of this coin.
Some info on the inscriptions:
Ruler: Maria Theresia
Legend (obverse):
R.IMP. HU.BO. REG. M.THERESIA. D.G. R.IMP.
(Romanorum Imperator Semper August) - Emperor of the Romans Ever August
HU.BO. - Queen of Hungary and Bohemia
REG. - Royality
M.THERESIA. - Maria Theresia
D.G. (Del Gratia) - By the grace of God
Legend (reverse): DUX.BURG. CO.TYR. ARCHID.AUST.
DUK.BURG. - Duchess Of Burgau
CO.TYR. - Countess of Tyrol
ARCHID.AUST. - Archduchess of Austria
Mintmasters Initials: SC
SC - Tobias Schobl and Joseph von Clotz Crowned imperal eagle with the Burgau coat of arms