Well if you're willing to steal everything, I hope you're also willing to pay for any potential consequences it has.
Ordination has its ways of coming around to those who merely take and don't give back, y'know? ;)

Quin, try this. Get an intervention scroll (doesn't matter too much which one) steal everything you need as fast as you can, and teleport your way out of there. Then get to the thieves guild fast to clear your name. Or, build up your sneak skill so that they don't notice you.

Slight spoiler!
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I found a very useful amulet that casts Chameleon 80% for 60 seconds on a bandit on the road between Gnisis and Ald Velothi. There's a woman there that ask you to fetch a ring of hers that have fallen into a pond, and when you pick it up she and a companion in crime of hers will attack you. It's the companion that carried the amulet. I might be a random item, though.

Just use the amulet, go into sneak mode and even someone with just a moderate Sneak skill is guaranteed success in the art of petty larceny.

The amulet of shadows is not a random item. You'll always find it in the spot you've described.

Quin, there are some NPCs in Molag Mar who wear glass armor. You can always taunt them into attacking.

Spoiler
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You will also get some as a reward in House Hlaalu.

Otherwise it all depends on how you want to play the game: buy, steal, taunt, or murder.

SPOILER!
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There's also a glass cuirass, boots and grieves on a dead guy at the Falasmaryon stronghold.

The armor is from a quest that you can complete in several ways. Only one of those ways will result in your character being rewarded with the glass armor.