The Zacatecas mint

The city of Zacatecas is the capital of the state of Zacatecas. Located in a rich mining area, the mint was first opened in 1810 during the War for Independence. 

The first Republican issue from this mint were dated 1825. The next ten years can be considered the "golden age" of the mint due to the interest of state governments in improving the facilities and investing part of the profits in productive projects, as was the case of Francisco García Salinas, who in 1831 channeled them to partially finance the Fresnillo mining negotiations.

However in September 1842, the central government leased the mint to the Anglo-Mexican Company, with English capital, which had already leased the mint at Guanajuato since 1825. That company was represented by the firm of Manning and Marshall, which shortly thereafter changed its name to Manning and Mackintosh.

The reaction of the people of Zacatecas was swift. A few days later, on 8 October 1842, a supplement to the newspaper El Siglo XIX{footnote}El Siglo XIX, Núm. 362, 8 October 1842{/footnote} published the claims that the City Council, the Departmental Board, the Court of Justice, the Board of Public Works, the Commercial Court, the regular clergy and and many individuals, sent President Santa Anna a request to have the contract annulled, arguing that it was a very poor deal. Despite this, the government complied with the contract, handing over the establishment to the company on 19 October 1842. The lease to Anglo-Mexicana was extended from fourteen years - as originally planned - to almost 32, including its ratification in 1845 and extensions in the years 1853, 1857 and 1862. (In March 1853 the provisional government of Manuel M. Lombardini leased the mints of Guanajuato and Zacatecas to Jecker, Torre y Compañía.  However, in May 1853 the new government of Santa Anna rescinded this contract without it being executed.)

The Zacatecas mint was eventually returned to the government at the same time as the Guanajuato mint in March 1874, in line with a policy to recover the administration of all the Mexican mints. However, this achievement was short-lived, for when Porfirio Díaz took up arms, at the beginning of 1876, the government of Lerdo de Tejada resorted to the same mechanism that several of his predecessors had used to obtain funds by renting out the mints. That same year, 1876, the Zacatecas and Guanajuato mints were leased together again to the same company called the Compañía Guanajuato-Zacatecana, made up of regional businessmen with a Board of Directors based in the city of Guanajuato, and a smaller junta in Zacatecas. This contract was extended in 1879 and 1883.

The Guanajuato and Zacatecas mint were returned to the government in mid-1895, and the Zacatecas mint remained in operation until 1905, the year in which it was decreed to be closed as part of the measures implemented in Mexico for the adoption of the gold standard.

Mint owners or lessees and their tenures

Assayers and their tenures (as evidence by coinage)

The assayers on its decimal coinage were:

Reales issues of the Zacatecas mint (¼, ½, 1 and 2 reales)

Quarter real 

KM-368.8 ¼r 1842 Z LR (Stack’s Bowers auction, 12 August 2024, lot 41347)

Diameter 12 mm. 0.845 g, 0.90277 silver

KM-368.8 ¼r 1842/1 Z LR (Stack’s Bowers Kirk Menczer Collection, 23 June 2026, lot 72061)

Interesting overdate in that no silver ¼ real dated 1841 is known from any mint.

Half real 

KM-370.11 ½r 1827 Z AO (Stack’s Bowers Kirk Menczer Collection, 23 June 2026, lot 72243)

Diameter 16 mm. 1.690 g, 0.90277 silver

For a consideration of the rarity of Zacatecas ½ real see here.

KM-370.11 ½r 1835/4 Z OM (Stack’s Bowers Kirk Menczer Collection, 23 June 2026, lot 72249) 

One real 

KM-372.10 1r 1869 Zs YH

Diameter 20 mm. 3.380 g, 0.90277 silver

KM-372.10 1r 1833 Zs OM –apparent retrograde “E” in MEXICANA

Repunched letters in the legend are common in Republic coinage. Poor quality, poor training or simply a lack of attention to detail by the mint are possible culprits in how these could have occurred. In this example, the “E” in MEXICANA appears to have been punched in retrograde and then punched correctly to eventually appear like a square “ ”.

Counterfeit

counterfeit KM-372.10 1r 1857 Zs MO (Briggs & Bustos Counterfeit issues, 22 February 2025, lot 31)

Struck in copper alloy. Remarkable execution of the engraving, very well struck.

Two reales 

KM-374.12 2r 1825 Zs AZ (Stack’s Bowers Kirk Menczer Collection, 24 June 2026, lot 73156)

Diameter 27 mm. 6.670 g, 0.90277 silver

KM-374.12 2r 1833/2 Zs OM (Stack’s Bowers Kirk Menczer Collection, 24 June 2026, lot 73165)

Reales issues of the Zacatecas mint (4 reales)

Diameter 32 mm. 13.540 g, 0.90277 silver 

KM-375.9 4r 1832 Zs OM (Stack’s Bowers Kirk Menczer Collection, 24 June 2026, lot 73295)

KM-375.9 4r 1833/2 Zs OM (Stack’s Bowers auction, 13 October 2021, lot 71519)

KM-375.9 4r 1838/7 Zs OM (Stack’s Bowers Kirk Menczer Collection, 24 June 2026, lot 73299)

KM-375.9 4r 1842 Zs OM (Stack’s Bowers Kirk Menczer Collection, 24 June 2026, lot 73304)

Variety with large letters.

KM-375.9 4r 1842 Zs OM (Stack’s Bowers auction, 13 February 2019, lot 71243)

Variety with small letters.

KM-375.9 4r 1845 Zs OM large “S” superscript

KM-375.9 4r 1845 Zs OM small “S” superscript

A variety that may get easily overlooked due to the subtlety of the superscript used in the dies.

KM-375.9 4r 1854/3 Zs OM (Ponterio Baltimore auction, 28 March 2011, lot 8436)

KM-375.9 4r 1857/5 Zs MO (Stack’s Bowers Kirk Menczer Collection, 24 June 2026, lot 73310)

KM-375.9 4r 1860/59 Zs MO (Stack’s Bowers auction, 13 February 2019, lot 71254)

KM-375.9 4r 1861/0 Zs VL (Stack’s Bowers Kirk Menczer Collection, 24 June 2026, lot 73313)

Counterfeit

counterfeit KM-375.9 8r 1837 Z OM

This is listed as Riddell No. 510.

counterfeit KM-375.9 4r 1842 Zs OM

Reales issues of the Zacatecas mint (8 reales)

KM-377.13 8r 1841 Zs OM (Stack’s Bowers Hong Kong Auction , 8 October 2022, lot 54473)

Diameter 39 mm. 27.070 g, 0.90277 silver

KM-377.13 8r 1828/7 Zs AO (Stack’s Bowers auction, 28 February 2024, lot 73330)

KM-377.13 8r 1858/7 Zs MO (Stack’s Bowers auction, 31 October 2023, lot 70900)

KM-377.13 8r 1865/4 Zs MO (Stack’s Bowers auction, 31 October 2023, lot 70914)

KM-377.13 8r 1882 Zs JS (Stack’s Bowers auction, 19 September 2025, lot 76476)

Variety with full "J" and mule of 1845-82 obverse die with 1882-86 reverse die.

KM-377.13 8r 1882 Zs JS (Stack’s Bowers auction, 16 May 2022, lot 63395)

Variety with straight “J”

KM-377.13 8r 1887 Z FZ (Stack’s Bowers auction, 26 August 2022, lot 34450)

KM-377.13 8r 1891/0 Zs FZ (Stack’s Bowers auction, 31 October 2023, lot 70949)

Displaying an overdate visible under magnification

KM-377.13 8r 1892/1 Zs FZ (Ponterio Baltimore auction, June 2011, lot 6619)

Counterfeits

counterfeit KM-377.13 8r 1829 Zs AO (Briggs & Bustos Counterfeit issues, 22 February 2025, lot 37)

Struck in silver.

counterfeit KM-377.13 8r 1831 Zs OM (Briggs & Bustos Counterfeit issues, 22 February 2025, lot 38)

Struck in silver. This is absent in Riddell, greater similarity of design on the side of the cap while on the obverse the eagle is thinner.

counterfeit KM-377.13 8r 1832 Zs OM (Briggs & Bustos Counterfeit issues II, 10 August 2025, lot 78)

Struck in low-fineness silver, 27.48 grams, 38.8 millimeters in diameter, medal alignment. Interesting contemporary counterfeit, notable for its exceptional similarity to the official issue of the Zacatecas mint, described by Riddell (no 223) as “admirably imitated, or perhaps genuine.”

Every design element matches the original, except for the edge, whose engraving is slightly less refined and shows weakness along the rim from 9:00 to 1:00 on the obverse side. Metal composition: 74.37% Silver, 20.62% Copper, 2.58% Zinc, 1.68% Iridium, 0.5572% Lead, 0.1536% Bismuth, and 0.0445% Gold.

counterfeit KM-377.13 8r 1841 Zs OM (Briggs & Bustos Counterfeit issues II, 10 August 2025, lot 79)

Struck on a flan of alloy commonly known as alpaca, 24.84 grams, 38.9 millimeters in diameter, medal alignment. Counterfeit not documented in Riddell’s work, identifiable by the backward “s” letters in the legend on the cap side, along with a reverse distinguished by the eagle’s curled feathers. Diffuse Republican edge cord at 12:00 and 6:00. Metal composition: 66.45% Copper, 16.85% Zinc, 14.98% Nickel, 0.6669% Iron, 0.66% Lead, and 0.3836% Cobalt.

counterfeit KM-377.13 8r 1842 Zs OM (Briggs & Bustos Counterfeit issues II, 10 August 2025, lot 81)

Struck on a low grade planchet. 26.65 grams, 38.2 millimeters in diameter, medal alignment. Easily recognizable by its distinctive Phrygian cap with rounded edges, surrounded by short and narrow rays. Eagle with narrow body and a noticeably smaller left wing. Slight differences in the legend typography. Crude edge design. Metal composition: 54.37% silver, 27.98% copper, 12.06% zinc, 3.48% nickel, 1.1396% lead, 0.76% tin, 0.1202% iron, and 0.0985% Bismuth.

counterfeit KM-377.13 8r 1844 Zs OM (Briggs & Bustos Counterfeit issues II, 10 August 2025, lot 80)

Struck on a flan of alloy commonly known as alpaca with low silver content, 21.16 grams, 38.7 millimeters in diameter, coin alignment. Specimen not reported by Riddell. Features a curious cap design that, when compared to a genuine piece, appears wider and slightly flattened. The reverse shows an eagle characterized by plumage composed of well-defined lines, with an apparent error in the legend: “REPULLICA.” Flan notably thin and the Republican edge cord appears somewhat crude. Metal composition: 56.57% Copper, 20.83% Zinc, 10.78% Nickel, 10.46% Silver, 0.6822% Lead, 0.3868% Cobalt, and 0.2933% Iron.