the number "22" will be the gold purity mark. This is a high quality piece, gold doesn't get much higher quality than this. 22K, 22ct or 916 (parts per 1000) or 91.6% gold (mainly Asia, Middle East) . Twenty two carat gold is Very yellow and Very soft.
The F letter could be a couple of things, a sponsor's mark or a Foreign import mark; UK - London & elsewhere on Imported SILVER or GOLD - ca 1842 - 1904. Hard to say without seeing the mark.
