Mexico 8 Reales Zs 1834 Om Medal Alignment?

Joan There is no error involved here.

In 1834 the Zacatecas mint used a medal die alignment on all coins. The coin die alignment was not introduced at this mint until 1842. During that year both types were made. Each of the branch mints converted in different years. Several switched back and forth one or more times.

There are of course errors in die alignment made throughout the Cap and Ray series but they are not so rare that there is much interest in them as a group.

LlacerSBD - Actually most Mexican mints used a coin alignment before 1845. There were 10 mints operating in 1845 and only three used the coin axis exclusively (EoMo from 1828, Guadaloupe Y Calvo from 1844 and Hermosillo from 1835). They are all scarce mints and most of the coin axis coins are rare to very rare.

The 8 other mints including all the high volume mints started as Medal Axis ONLY. The dates of conversion to coin axis are:

Chihuahua 1840
Durango 1842
Guadalajara 1833
Guanajuato 1843
Mexico City 1827
San Luis Potosi 1849
Zacatecas 1842

The rest of the Mexican mints opened after 1845:

Alamos opened 1864 - all coin axis
Culican " 1846 - all coin axis
Oaxaca " 1858 - all coin axis

Therefore nearly all production duting the 1820s and 1830s (except for Mexico City itself) was medal axis.