Based on the provided reference, a guinea coin from the time of King George III contained 7.7 grams (0.25 troy ounces) of gold.
The amount of gold in a guinea coin varied slightly throughout its history due to changes in coinage standards. However, the reference specifically details the composition of the guineas minted during the reign of King George III, particularly as determined by an assay in 1773.
Understanding the Composition of a Guinea
Let's break down the key specifications of a King George III guinea coin according to the source:
- Total Weight: 8.4 grams (0.27 troy ounces)
- Diameter: 25 mm (0.98 inches)
- Gold Purity (Fineness): 0.9146 (equivalent to 22 carat gold, where pure gold is 24 carat)
- Gold Content: 7.7 grams (0.25 troy ounces)
This means that while the coin weighed 8.4 grams in total, not all of that weight was pure gold. The remaining weight consisted primarily of copper, which was added to make the coin more durable. The purity of 0.9146 indicates that 91.46% of the coin's weight was gold.
Key Specifications Summary
Here is a quick look at the details for the George III guinea mentioned:
| Specification | Value |
|---|---|
| Period | King George III |
| Total Weight | 8.4 g (0.27 ozt) |
| Diameter | 25 mm (0.98 in) |
| Gold Purity | 0.9146 (91.46%) |
| Gold Content | 7.7 g (0.25 ozt) |
This specific gold content of 7.7 grams is based on the 1773 assay referenced, providing a precise measure for guineas of that era.
For more details, you can refer to the Guinea (coin) - Wikipedia page.
