What you want to do is called table top photography.
The key word is "macro".
Most digital cameras will let you put the lens into macro mode for close focusing. In macro mode you can focus down to inches from the lens.
Lighting is also a key word. You cannot depend upon the flash to properly illuminate your subject with the lens so close to the object. You will have to provide lights to properly illuminate the subject.
The camera to choose depends upon your pocket-book.
The price ranges from a few hundered up to many thousands of dollars.
What is your budget for this project???
...
I am looking to buy a digital camera specifically for photographing small objects, jewellery and plants, as well as artwork, could anyone give me some advise on the types of camera that would be suitable or the features i would need to look for when choosing one.
Thankyou

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic