I found the answer to what the "325" means... It is valuable according to this information:
What does the stamp 325 mean on jewelry?
Answer
That indicates the purity of the metal. Coins and gold bars are usually 999,9 out of 1000. In this case, the item contains 325 out of 1000 parts of pure (gold). In jewelry, the rest is usually filled with fine gold and gold mixed with other fine metals.
Sterling silver has a purity of 975 out of 1000.
I believe 10K FG means 10 Caret Fine Gold.
When a ring is marked "10k FG," it indicates that the ring is made of 10-karat gold and features a fineness grade (FG) that suggests it may have a specific quality or standard associated with its gold content. The "10k" signifies that the gold is 41.7% pure gold, with the remainder typically composed of other metals for strength and durability. The "FG" can sometimes denote a particular manufacturer or designer's mark, but its specific meaning may vary, so it's best to consult a jeweler for clarity.
10 feet killograms
filled golg wedding ring
95% platinum
14k fg wedding band
14K FG inside a gold ring stands for 14 karat fine gold. The "14K" indicates the purity of the gold, with 14 karat gold being composed of 58.3% pure gold mixed with other metals for strength and durability. The "FG" likely stands for "fine gold," indicating that the gold used in the ring is of high quality and has a higher gold content compared to lower karat gold alloys.
"10k p fg" typically refers to a measurement in micrograms (µg) of a substance per 10,000 parts per gram (p/g). This notation is often used in scientific, environmental, or chemical contexts to indicate concentration levels. It signifies how much of a particular substance is present in a specified amount of a mixture or sample.
fg
FG are the initials of Frank Gasparro, who designed the Lincoln Memorial reverse.
FG stands for the designer of this coin, Frank Gasparro.
If the "A" is set at an angle, it is more likely not an A after all, but a G. Fredrick Goldman is a ring manufacturer that uses the "FG" jewelers mark. The F is vertical and the G is slanted or stylized.