1. The codename for a British
signals-intelligence satellite originally
intended to be launched in 1988. The
revelation of the existence of the Zircon
project (which had been concealed by the
government), and the government's subsequent
efforts to suppress a programme about it on
BBC television, caused much controversy in
1987. Its function would be to intercept
radio and other signals from the USSR,
Europe, and the Middle East and transmit them
to the Government Communications Headquarters
in Cheltenham, England.

2. Zirconium silicate, ZrSiO4, a mineral that
occurs in small quantities in a wide range of
igneous, sedimentary, and metamorphic rocks.
It is very durable and is resistant to
erosion and weathering. It is usually
coloured brown, but can be other colours, and
when transparent may be used as a gemstone.