Types of Spanish Coins

Most Spanish coins that circulated in the US were minted in Central and South American Spanish colonial countries. There is only one type of coin that was minted in Spain and intended primarily for homeland use that is seen on our early paper money. 

There were three main types of Spanish colonial silver coins (gold and copper coins were not used as vignettes on US obsolete notes): cob, pillar, and bust. Only the bust coinage is known to have been used on US obsolete notes.

• Cob coinage--coins crudely produced without modern machinery until the early 18th century.
• Pillar coinage--"milled" or machine-made coinage minted from 1732 until 1772.  These depict a vignette of old and new worlds topped by the crown of Spain.  There was no ruler's portrait.
• Bust coinage--milled coinage from 1772 until independence, 1821-25.  These display the bust of the reigning king.

It is the bust coinage that was used on United States obsolete paper money.  The denomination is the real.  The largest coin is the 8 reales.  The fineness and weight of the US silver dollar was directly modeled on that of the 8 reales.  Subsidiary coins are 4 reales, 2 reales, 1 real, half real, and quarter real.  All but the quarter real are found on US obsolete notes.

The bust coins of Spanish colonial Mexico, Peru, Bolivia, and Guatemala appear on US obsolete notes.  This type of coin was also produced in Chile and Columbia, but their coins were not used on US notes. The country of origin of the coin is determined by the mintmark on the reverse of the coin.

In addition, the coins bear assayer initials, usually two, since there were commonly a pair of assayers responsible for the coin's purity and weight of precious metal.  Each country had its own assayers, and different pairs of assayers with different initials worked over the mintage span of a coin.

The figure below shows a Mexican 8 reales reverse.  The location of the mintmark and assayer initials is shown.  The denomination mark--in this case "8 R"--is between.  The layout of the subsidiary coins, except for the quarter and half real, is similar.  The quarter real image has not been found on US notes. 

The denomination/mintmark/assayer layout for 8, 4, 2 and 1 reales coins is this:

mintmark -- denomination -- assayer mark

The half real layout is this:

R (used for half real) -- mintmark -- assayer mark

See the coin images below for examples.