There is no such thing as white gold.
There are although gold alloys which seem white, silvery, or grey.
When jewellers speak of white gold, they mean white gold alloys. In most other major languages these alloys are described as grey rather than white. We will stick to "white".

Gold is a yellow metallic element but, in its pure form, it is too soft to be used for general jewellery purposes, although there are some cultures which do wear pure gold jewellery, it would need to be solidly made and cautiously used. The yellow colour of gold is caused by gold engrossing violet and blue light, but reflecting yellow and red light.