Trolls and Laurelin’s last fruit.

[Hookbill the Goomba]

In reply to "Hot, crispy nice hobbit ".

I'm not sure about that. Did Trolls ware clothes? I don’t think I remember reading of that anywhere... You may be confusing an image often given to trolls in interpretations of The Hobbit. But as you say, if they did ware clothes I'm not sure if they would have been turned to stone, after all when water boils at 100'C the container its in does not boil also. (Unless its something stupid like chocolate, so we’ll assume its glass for all you smarty people who point out little mistakes… I personally am one of them so I like to cover my tracks )
That’s not perhaps a good analogy, but I can’t think of a better one now. Besides, if 'Magic' is intelligent I don’t suppose it would bother whether it turned the clothes to stone also. It was the trolls themselves that were of the breed of Melkor not the clothes.
Gandalf declares to them

"Dawn take you all and be stone to you!"
Gandalf, In "The Hobbit", chapter 2, Roast mutton

I would emphasise the YOU in this, I take it that it is the creatures themselves that are turned to stone.

The trolls Bilbo met were stone trolls, that name given to them as they turned to stone. Tolkien never says that other trolls do so... But then again in roast mutton it suggest that this is for all trolls,

; For trolls, as you probably know, must go underground before dawn, or they go back to the stuff of the mountains they are made of and never move again.

So it told seem that Tolkien used "Trolls" as a collective, and so means all trolls... Would you not say? Is it for all trolls that daylight means death?

The encyclopaedia of arda has this to say on the subject of stone trolls;

A race of trolls in the service of Sauron. We know nothing for certain of these creatures except that they inhabited the Westlands of Middle-earth: the trolls encountered by Bilbo Baggins and his companions on their journey to Erebor were likely of this kind...

Actually, the three trolls encountered by Bilbo and company are never explicitly identified as 'Stone-trolls', but the circumstantial evidence for this quite strong. Quite apart from the fact that they actually turned to stone, Tolkien mentions that '...in the Westlands the Stone-trolls spoke a debased form of the Common Speech' (The Lord of the Rings Appendix F 1), a comment that matches Bert, Bill and Tom well, but is hard to explain in any other terms.

Back on topic...
The light of the Silmarils, as said, contains the same light made from the two trees, Earendill's star, as you know, id the Silmarill upon his brow, so the pile of Galadriel too possesses the same light. So the theory of that being a death device for Trolls is a sound one.

P.S.
"Hide Da boss is coming!" one troll,
"Howdy, troll, how’s it shakin?... oh no, not again!" Morgoth...
That’s how I assume that would go

[Hot, crispy nice hobbit]

Trolls wear clothes! In the Hobbit, they have got pockets in which they keep purses! The reason why Bilbo was captured by William is because he tried to pickpocket him, remember? Then again we are told that the clothes themselves turn to stone!

He held out a largish key, though no doubt William had thought it very small and secret. It must have fallen out of his pocket, very luckily, before he was turned to stone.

I had been very irked at this statement, particularly the words, "very luckily". You see, if William's clothes did not turn to stone, they would be able to search the stoned trolls for loot and stuff. Apparently, the dropping of the key was "lucky", simply because the clothes, including the pocket and the stuff inside, are now inaccessible to the party!

Which leads me to another fancy: did Prof Morgy designed those clothes as well?

"This fabric is so soft and silky!" - female troll customer
"Of course! It is Angband Cement, imported from the far north..." female troll attendant

On the other hand, it just struck me that since Morgoth wore the Silmarili inside of Angband for an entire age, it must be bright as broad daylight in the bowels of his foul fortress/laboratory every day for an entire age! I have to agree with Olorin_TLA that it is pure torture!

"Arrgh! Just get out of my sight! This room is bright enough!" Prof Morgy to blindfolded Balrogs

[Olorin_TLA]

Can't say i agree with "Dawn take you all and be stone to you!" having any bearing on the clothes issue...saying"Dawn take you all and be stone to you, and your clothes!" is hardly very dramatic, and I actually can't imagine anyone saying it. For instance, when Gandalf tells of his fight with the Balrog, he says "I was burned" - presumably therefore his clothes were burned too (but that's for another thread!) but it's too...mundane...to be worth mentioning really.