Coins are not always round, and Mexican cobs of the seventeenth and early eighteenth centuries provide some of the most dramatic examples. As Daniel Sedwick (Member #2) described in the Straps for Cash article, they produced their blanks by pouring silver onto a flat surface in a long strap, or riel, letting it spread and cool naturally, then cutting it into individual planchets. The cut edges and sharp points were subsequently hammered down before striking, creating the irregular curves, angles, indentations, projections, and other distinctive forms characteristic of Mexican cobs. The end pieces of these silver straps could be especially unusual.
Formed over more than fifteen years, this collection was built specifically around those naturally created mint shapes. Rather than collecting only by date, assayer, or variety, the emphasis was placed on the style and silhouette of each flan and on the unusual forms produced through the pouring, cutting, hammering, and striking process. Certain pieces retain natural flowing edges from the original silver strap, while others display dramatic cuts, hammered points, deep indentations, unusual projections, or openings created during the cooling of the silver.
The collection ranges from 1/2 real through 8 reales, with the great majority being 8 reales, and is centered principally on Mexico City issues of Charles II and Philip V. Many examples also carry important shipwreck, hoard, countermark, dates, die variety, and important pedigree associations.
An S1 through S4 classification in the code for each coin number was developed by the collector to describe the relative rarity and distinctiveness of the different shape styles, with S4 representing the most dramatic or complex forms. Together, the coins form a specialized study of the remarkable natural shapes created by the historic production methods of the Mexico City mint.
NOTE: The above coins will be part of the Sedwick Auction 40 (Session 3: Cobs of Mexico, Lima & Potosi), which will take place on November 5, 2026. To view these coins and others, please visit Sedwick Auction 40.
Also view our Treasure of the Month for October 2026, which featured two other odd-shaped coins, as well as the article, Straps for Cash, referenced in this post.
