New evidence for the Arkenstone-Silmaril case

[Feanor of the Peredhil]

I rather like this thread, it has a lot of good points, but some are a little incomplete, off, or confusing:

"I just don't think that JRRT would allow one of the items central to the history of ME to end up in Thorin's grave."

Why not, Saucepan Man? He allowed the One Ring into the hands of a boring little Hobbit, why wouldn't he allow a different 'central item' into the hands of a Dwarven lord?

"Nevertheless, it would seem odd to me for dwarves to make such a significant dwelling in a place that would only produce diamonds."

Volcanic eruptions yield not only diamonds, but also peridot, and if my memory serves me, rubies and other such gems.

"If the Silmaril had been floating around in magma for a long time, wouldn't it have become crusted with lava? Then the dwarves could have basically scraped it off. That could account for the cutting and fashioning could it not?"

No. It's so hot 'floating around in magma' that it would impossible for it to cool long enough for a crust to form. And, although scraping of lava could account for cutting and fashioning alone, technically they wouldn't be fashioning the stone itself.

These points argue both for and against the Silmaril theory, but my question is, if the Arkenstone is NOT a Silmaril, then what type of stone could it be made of? A moonstone perhaps, since they are said to glow as does the moon, hence the name? An actual many faceted diamond (and that brings my question 'how did Dwarves cut diamonds?' into play), perhaps?

A very interesting thread. My regards, Gwaihir.