There are a few different things to go at here...
1. Your shot is overexposed, which has killed the colour saturation
2. The lighting is far too flat, you need perhaps 1 gentle fill light and a few tiny light sources to create small highlights. bits of screwed up kitchen foil may do that job for you, just out of shot, if you don't have small lights. A light tent is the worst possible approach.
3. The white background doesn't help How often have you seen a white display stand used in a jewellery shop> Black is the colour of choice, it creates the contrast needed.
a daft question: how do I get rid of the black shadow (that is me and my camera) at the front?
It isn't a shadow, it's a reflection. Put a large piece of white card in front of the camera, just make a hole in it big enough for the lens, and stick it through the hole. Then you will only get a reflection of the lens, not of the rest of the room. Most of us go the other way though, we arrange things like black card, coloured lights and so on, around the camera to
create reflections
