Freelance work - jewelry animation

I had received an offer of creating a presentation video/animation for a jewelry company. The request is to model, texture and animate a sort of camera closing in on a ring box, which opens up. The camera hovers around the ring itself and then zooms back out, with the lid of the box closing.
The provided reference images were helpful enough in establishing the main visual style of the video and I had 10 days to finish the job. My aim was to learn from my previous experiences and pretty soon after the first talk, I wanted to send a somewhat roughed out test render to the client. There are multiple reasons behind this:

 1 - by sending a piece of work soon after the initial talk, you give the impression of being someone very active and committed to the job. It reassures the client of you being the right choice and they don't have to bite their nails up until the deadline day, wondering whether you will deliver or not. 
 2- by providing early test images, the client can immediately point out the visual direction you need to head in. If he/she can rule out an issue early on, that will save you time and money. Eliminating problems at the very early stages can save you a lot of headache. 

 Reference images:

The first step was to build the models with good proportions. At first, I had doubts about the ring itself as I didn't really understand the exact shape of the diamond itself, but I`ve managed to gather some schematics which cleared things up. This schematic was not provided by the client, so often times you have to gather your own... you won't be provided with absolutely everything.

Breaking down the reference:

   
It's really helpful to go in and examine the reference and make scribbles, notes. It makes you more aware and familiar with what you need to create.
The light is coming from above with a whitish color. The light is sort of a sky light with very scattered and smooth behaviour, hence the shadows are soft as well. The surfaces have a gradient type of shading. On the front of the right box you notice a kind of radial transition from light shade to dark around the edges.
This shading can be reproduced by positioning the lights appropriately and adjusting the material accordingly. That said, there is another technique, which involves hand painting in these shades directly in to the texture. So, if render times become an issue, or if simply the latter solution seems simpler, I will choose that.