When you finish getting the pictures for Big Zeke on Safari, he will give you his old hardhat as a reward.
Get a camera by finding the gold nugget in the tree at Kaya Forests, and swapping it for the camera at Nabooti. Take photos of all 7 animals. You need the hardhat to enter the Diamond Mine.
(see related question)
You get a hardhat from Big Zeke when you complete the Safari. You need a helmet to enter the Diamond Mine.
When you complete the Safari on Nabooti island, Big Zeke gives you his old Hardhat. You can use this to enter the Diamond Mine. (see related question)
In the diamond mine is the White Jewel.
you get a gem in the mine
There is no oil can on Nabooti Island. For the Diamond Mine, see the related question below.
You need a helmet to (briefly) turn off the electric fence at the Diamond Mine. Get one by playing the Safari. You can get a camera at Nabooti by swapping the gold nugget (in the second palm tree at Kaya Forests).
At the bottom of Africa
the white jewel.
You use the digital camera to help out Zeke by taking 7 good pictures of different animals and he gives you his mine helmet for the diamond mines.
at the botttom of the map of Africa
In the diamond mine after you go into the mine where there is a wall blocking t he way. ;)
watch out for mine carts