Decimal issues of the Guanajuato mint (gold)

One peso

KM-410.3 $1 1888 Go R (Morton & Eden sale 104, November 2019, lot 633)

Diameter 15 mm.1.692 g. 0.8750 gold 

KM-410.3 $1 1894/2 Go R (Briggs and Bustos auction X, 8 November 2024)

"The key date of the series with 180 specimens reported. Uncatalogued overdate 4/2, since there are no known or registered pieces dated 1893 besides which the curve and the lower part of the 2 is distinguishable."

KM-410.3 $1 1898 Go R (Stack’s Bowers auction, 3 September 2025, lot 45581)

Muled With 5 Centavos Obverse

2½ pesos 

KM-411.3 $2.50 1871 Go S

Diameter 18 mm. 4.230 g. 0.8750 gold 

KM-411.3 $2½ 1888 Go over Mo (Briggs & Bustos auction VIII, April 2024, lot 382)

Last date struck at the Guanajuato mint in this rare denomination, the key piece with a mintage of only 110 pieces reported. Elusive as are all the 1888 issues, a very interesting fact is that all of these were struck with a reverse with a re-engraved Go/Mo mint mark, none of them show any trace of an over-assayer. 

Five pesos 

KM-412.4 $5 1871 Go S (Morton & Eden sale 104, November 2019, lot 647)

Diameter 22 mm. 8.460 g. 0.8750 gold 

The mintage for 1871 was just 16. One wonders why they would bother to strike such a small quantity. We do not definitively know the answer but again speculation abounds. The mint was required by law to produce coins on demand if provided with the gold necessary to mint them. Guanajuato was a wealthy mining town and obviously had some wealthy citizens. Some people speculate that the daughter of such a citizen was getting married and “los padrinos y madrinos” or couple’s wedding sponsors wanted to give the “arras”, the traditional wedding gift of 13 gold coins. Wedding sponsors are like godparents. The coins are blessed, given to the groom who presents them to the bride during the wedding ceremony. The easiest way to give the mint the gold needed to produce at least thirteen 5 pesos would be to provide four 20 pesos. The four 20 pesos would produce sixteen 5 pesos coins. This may not be what actually happened, but it is a lovely story.

Ten pesos 

Diameter 27 mm. 16.920 g. 0.8750 gold 

Twenty pesos

KM-414.4 $20 1870 Go S (Stack’s Bowers auction, 26 August 2025, lot 41436)

Diameter 34 mm. 33.840 g. 0.8750 gold 

KM-414.4 $20 1871/0 Go S (Stack’s Bowers auction, 24 June 2021, lot 72371)

Though unlisted in KM as an overdate, this example clearly presents the remnants of a 0 under the final digit.

KM-414.4 $20 1873/1 Go S (Stack’s Bowers NYINC auction, 13 January 2023, lot 21243)

KM-414.4 $20 1883/2 Go B (Stack’s Bowers auction, 26 August 2025, lot 41438)