Is there an object that grants force usage to non-force users?

No. You must take either start with a Force career/spec or take a Force unispec to be granted a Force Rating.

http://starwars.wikia.com/wiki/Artusian_crystal

As a gm how would you handle this?

Could a player use it to gain a force sensitivity? Maybe gan a single force die?

I would treat as plot device that would be a part of the narrative on why a character would take a Force unispec. Not a fan of handing out Force Rating without a cost.

What's the end state objective?

Granting FR 1 to a player is kinda a big deal, but the source material gives us options, namely that in JK the crystals gave you force fuel...

So, instead of having an item give a boost to whoever holds it, why not make it expendable? Each crystal grants a feature or effect that lasts till the end of the encounter, then fizzles out. So like one gives a rank or two in reflect, another Move with an upgrade or two at FR1, so on.

That way you could allow the player to rock out from time to time, but you control how and how often...

I'm thinking that the character is a scientist then artisan than shadow, the crystal is used in a cybernetic device that gives him mechanical force aptitude, it would be instead of a force emergent spec and it would be like he took sentinel as a career instead of engineer-scientist.

Why not just have him start with Sentinel/Artisan but avoid taking any Force powers or talents initially and fluff the getting of the Force Rating later?

Thats the idea if I do another pbp, however I already have this character as a scientist.