By Allan Fuller
April's quiz question was:
The April gemstone is diamond. Where in London is the world's largest Diamond, and who owns it?
The Cullinan Diamond is the largest gem-quality rough diamond ever found, weighing 3,106 carats (621.20 g), discovered at the Premier No.2 mine in Cullinan, South Africa, on 26 January 1905. It was named after Thomas Cullinan, the owner of the mine.
In April 1905, it was put on sale in London, but despite considerable interest, it was still unsold after two years. In 1907, the Transvaal Colony government bought the Cullinan and Prime Minister Louis Botha presented it to Edward VII, the British king who reigned over the territory, and it was cut by Joseph Asscher & Co. in Amsterdam.
Cullinan I, or the Great Star of Africa, is a pendeloque-cut brilliant weighing 530.2 carats (106.04 g) and has 74 facets It is set at the top of the Sovereign's Scepter with Cross which had to be redesigned in 1910 to accommodate it.
Other parts of the stone were incorporated into the Crown Jewels which have been kept at the Tower of London since the 1660s, where they have attracted visitors ever since.
Congratulations to Andrew Parsons, whose name was picked out of the hat to win April's Quiz - please email firstname.lastname@example.org to arrange the means of receiving your champagne!