1851-1856 AD., Austro-Hungarian empire, Kremnitz in Hungary, Habsburg rule, Franz Joseph I, ½ Kreuzer, KM 2181.

Austro-Hungarian empire, Kremnitz in Hungary, Habsburg rule, Franz Joseph I, engraver: Johann Weiss, Kremnica / Kremnitz / Körmöcbánya mint, 1851-1856 AD.,
½ Kreuzer (ø 19,7 mm / 2,68 g), copper, 2,70 g theor. mint weight, mintage 27.733.000 , axis medal alignment ↑↑ (0°), plain edge,
Obv.: K·K·OESTERREICHISCHE SCHEIDEMUNZE· , crowned imperial double-headed eagle, on the breast the arms of the Austro-Hungarian Empire, with collar of the Golden Fleece, carrying a sword and the imperial orb (legend for "Kaiserliche und Königliche Östereichische Scheidemünze" , Imperial and Royal Austrian low metal value coin).
Rev.: ½ / KREUZER / 1851 / B , fractionnary value, date and mint mark below.
KM 2181 .

Year / Mint Mark / Mintage
1851 A 3.07 Vienna, Austria
1851 B 27.733.000 Kremnica, Hungary then, (1851 B was minted between 1851 - 1856)
1851 C 100
1851 E
1851 G rare

(a Scheidemünze is a common coin for which the metal is worth less than the face value).

The Kremnica Mint (Slovak: Mincovňa Kremnica) is a state-owned mint situated in Kremnica, today Slovakia. The predecessor of current Mincovňa Kremnica, š. p. (štátny podnik = state company) was established in 1328, and for nearly seven centuries it has continuously been producing mint articles.
Kremnica Mint was established in 1328 when Kremnica was promoted to a free royal town by the Hungarian King Charles Robert of Anjou; the mint issued several kinds of coins early on, of which the most successful was its ducat. Kremnica ducats were well-known because of their good quality and were considered the hardest currency in Central Europe. Available historical records report that 21.5 million ducats were minted at the Kremnica Mint throughout its history. The aggregate value of this amount, measured at today's prices of gold, would be three billion US dollars (exclusive of the numismatic value).
The mint became very outdated by the beginning of the 20th century, and many called for new equipment and for the mint to be moved to Budapest. However, this did not happen until the end of World War I. As the Czech troops invaded Northern Hungary, the Károlyi government ordered to move the equipment and noble metal stock to Budapest. The Hungarian Government started to mint the first coins with the faulty machines and worn-out dies in Csepel. Even coins minted in 1922 bore the KB mint mark.
More on https://en.wikipedia.org/wiki/Kremnica_Mint