In that sentence, jewel is what I call a lexaphor. Roughly, a lexaphor is a metaphor in a single word. The above is about the same as:

I'll have something in my resume as valuable as a jewel.

I have already stressed using different forms; the lexaphor is a very important form to use.

1. He felt empty (lexaphor).
2. He felt like an empty container. (simile)

People aren't actually empty. He is being described as if he was a container in #1, so there's an implied simile to containers (#2). "Empty" has been used so often in this role that it has become part-word and I would not be surprised the find the metaphorical definition in the dictionary.

The default is to understand something as literal, so every figurative expression has to have a cue. The cue for a lexaphor is that the thing cannot literally have the trait. For example, a jewel cannot be in a resume.

If you assign an inanimate object a trait that could belong to a person, that's called personification. That's one kind of lexaphor, but only one kind. The attention to personification unfortunately hides the more general principle.

1. My melancholy was like a ripening fruit. (simile)
2. My melancholy was a ripening fruit. (metaphor)
3. My melancholy ripened. (lexaphor. From The King of Lies)

Fruit ripens; literally, melancholy does not. So #3 creates an implied metaphorical to fruit.

1. That left me with the cut of being ignored.
2. The left me with the paper cut of being ignored.
3. That left me with the scabbed-over cut of being ignored.

So now it's a metaphor in a phrase, but the principle is the same. It's easy to use a familiar lexaphor (like cut or jewel); consider if a modifying word can increase descriptive accuracy, because it will surely increase freshness.

I think the following is a very long lexaphor. (Or something too difficult for me to analyze: Brian Frosh, slamming the attorney's on the other side:

I think they may have violated Lewis Carroll's copyright on 'Alice in Wonderland.' (reported by Newsweek)

I could feel the misery coming off of her in waves (Hart, The King of Lies).

in a pilgrimage of fumbled words (page 40)

1. The glare she gave old Bob was a laser that melted him in his seat. (metaphor)
2. She gave old Bob a laser glare that melted him in his seat. (lexaphor, Teen Inc., page 4)

And with that knowledge, the ability to look her in the eyes ever again opens the emergency exit and jumps out of the plane.
My libido, however, stays firmly in place.
(Intercepted, Martin, page 219 trade, the scene occurs in a plane)