is the arkenstone one of the silmarils?

What if the witch was hoarse?- Halfwise

Aren't all witches hoarse? Comes as a package with the cackle, warty nose and one tooth.   

On the plus side they are always in black so we know for definite what colour.  

Witches are hoarse from shouting at dumb arse princes, kings & twonk heads who dont do as they are told  
Thats why said twonk heads have to be bewitched ! And horses are very handy at giving a kick up the jacksee, have you been clobbered by a solid iron horse shoe with a driving force of half a ton ?

Ive had a horse stand on my foot (more than once) bloody painful!!!     

a horse bit my finger once... that hurt. (i had eaten chocolate and i guess the horse thought my finger was food)

Finger food....?

I've seen a horse kick someone (my mom) and break some of their ribs.
Horses can be dicks, even if it's the owner's fault. Raise hamsters instead!

They certainly are hard to shift when they are standing on your foot, that I do know!   

What ? hamsters ?  

Hamsters and ferrets are another good reason for wearing a kilt. I cant think of anything worse than some small hairy thing clambering up inside your trouser leg- well maybe Halfy as I suppose- but nothing else!   

Need a lore check please!!

A wiki entry says that 'arkenstone' and 'silmaril' share a root in Tolkiens languages- is this accurate or just a spurious wiki entry?

Maybe it's a refernce to Tolkien's use of eorclanstánas for 'Silmarils' in an Old English translation of one of the early 'Silmarillion' texts [possibly one of the Annals, I can't recall which early text at the moment]?

I would have to see the entry in question I guess.

Well, that's cool, Elthir. You really need to get a life, you know... But no, best you stay attuned to all things Tolkien -- for our benefit.

It wasnt much of an entry Elthir, hence my suspicion of it, all it said was that the two words were related in Tolkien's languages- no other explanation or any examples were given.

Hmm, I guess one could call this a 'relationship' but Arkenstone is not a word from Tolkien's invented languages in any case, and must be seen as a translation within The Hobbit. JDR theorizes that Arkenstone, 'rather than a modernization of the Old English (...) could represent an anglicization of Old Norse.'

iarkna-steinn Elder Edda, eorcan-stan Old English, [postulated] Gothic airkna-stains [Jacob Grimm, Teutonic Mythology]

In any case the relationship meant in the Wiki, as far as I know anyway, would seem to be as I guessed: that Tolkien used the Old English Eorclanstanas 'precious or holy stones' to refer to the Silmarils, and in an Old English version of the Annals of Beleriand for example:

Morgoth... genom tha eorclanstanas Feanores 'Morgoth stole the Silmarils of Feanor'

Otherwise I cannot think of an Elvish base that leads us, in theory, to both words being related, such as for arguable example [forgive my lack of the proper diacritics], that the word Nom:

' [Nom] must be related to the Elvish bases NGOL- 'wise, wisdom, be wise' and NGOLOD- 'one of the wise folk, Gnome' as well as NOWO- 'think, form idea, imagine'; and Tolkien obviously devised these forms to imply a genetic connection with IE [Indo-European] gno- 'to know', the root of which led to the Greek [word written in characters I cannot produce] 'intelligence, thought'.

Editorial response to a letter reacting to Words And Devices, Vinyar Tengwar 19

That's a kind of relationship connecting Elvish [theoretical] bases to Primary World words.

In depth and informative as always Elthir.
But it seems to thin a connection to me. I do think Tolkien used similar imagery, which as a writer is fair enough given he thought the Sil would never see the light of day (and he was right within his own lifetime) but beyond that I dont think he intended for there to be any connection between them, even in the language.
Any similarity of meaning drawn form a root owes more I think to hs using similar wording in his description nothing more.