How to Identify the Spade Guinea

What Is It

The Spade Guinea is a gold guinea coin struck under King George III between 1787 and 1799. It takes its popular name from the shape of the royal arms shield on the reverse, which resembles the pointed, flat-topped blade of a garden spade rather than the rounder shield shapes used on earlier or later guineas. Its attractive, well-defined shape has made it one of the more recognizable and collected guinea types.

Obverse Design

The obverse shows George III's bare head facing right, with the legend GEORGIUS III DEI GRATIA around the rim. The portrait style is plain and unadorned compared with earlier bewigged royal portraits, reflecting the simpler neoclassical taste of the late 18th century.

Reverse Design

The reverse features a crowned shield shaped distinctly like a spade, quartered with the pre-1801 royal arms (England, Scotland, and Ireland, with an inescutcheon for Hanover), surrounded by the Latin legend M B F ET H REX F D and the date below the shield. The crisp, geometric outline of the spade shield is the defining visual feature of this type.

Size, Weight, and Metal

The Spade Guinea is struck in 22-carat gold, weighs approximately 8.4 grams, and measures around 25mm in diameter, consistent with other late 18th-century guineas. The edge is milled.

Mint Marks and Where to Find Them

All Spade Guineas were struck at the Royal Mint in London during this period, so no branch mint marks are present. Identification instead relies on the date below the shield and the distinctive spade outline itself.

Telling It Apart from Similar Coins

Earlier George III guineas used rounder or more traditional shield shapes, while later issues after 1813 (the "military guinea") returned to a different design altogether, so the sharply pointed spade shield is unique to the 1787-1799 run. Comparing the shield's silhouette against reference images of other guinea types is the fastest way to confirm a spade guinea specifically.

Judging Condition at a Glance

Because the Spade Guinea was popular and widely used, and its attractive shape made it a favorite for jewelry mounting, wear is common on George III's hair curls and cheek, and on the raised crown and shield edges on the reverse. Since so many surviving examples were later mounted as pendants, brooches, or watch fobs, checking the rim carefully for solder residue, bent edges, or drilled holes is essential before assuming a coin is in original, unaltered condition.

Authenticity Red Flags

Because of its popularity for jewelry, look closely for signs a loop or bezel was once soldered or clipped off the rim, which reduces both authenticity and value as a coin. Weigh the piece and compare its color and luster to reference gold guineas; a coin that is too light, has soft or mushy lettering, or shows file marks around the edge may be a later cast copy or an ex-jewelry piece that has been altered or repaired.