The old, pre-decimal Sixpenny piece or sixpence. This coin was mentioned in many children's nursery rhymes.

Sing a song of sixpence, 
A pocket full of rye,
Four and twenty blackbirds
Baked in a pie.
When the pie was opened,
The birds began to sing.
Wasn't that a dainty dish
To set before a king? 

The farthing was one quarter of a penny. In Victorian times or earlier, young girls would sing this song in London in order to sell their buttons:

Buttons, a farthing a pair!
Come, who will buy them of me?
They're round and sound and pretty,
And fit for girls of the city.
Come, who will buy them of me?
Buttons, a farthing a pair! 

Simple Simon met a pieman
Going to the fair;
Says Simple Simon to the pieman,
"Let me taste your ware."
Says the pieman to Simple Simon,
"Show me first your penny."
Says Simple Simon to the pieman,
"Indeed, I have not any." 

We lost all these interesting coins and names when we went to decimal coinage in 1971. The silver coloured coin shown above is the "Half Crown" which is worth a ¼ of a pound (£1).

Value of Coins
4 farthings = 1 penny (1d) 
2 ha'pence = 1 penny (1d) 
3 pence = 1 thruppence (3d) 
6 pence = 1 sixpence (6d) 
12 pence = 1 shilling (1s) 
2 shillings = 1 florin (2s) 
2 shillings and 6 pence = 1 half crown (2s 6d)