Turquoise is a blue-green mineral that is a compound of aluminium, copper and hydrous phosphate.
Turquoise has been used for thousands of years in jewellery and for other decorations. Turquoise is also used to describe the colour of the stone.
Yellow is a very bright colour often seen on insects, fruits and flowers. It is a primary colour, which means yellow paint can be used to make other colours but you can't use any other colours to make yellow paint. The bird in the picture is yellow.