Can you even clearly distinguish these possible pronunciations? I can't decide precisely which of these four I say:

(1) jool, single syllable, pure long vowel
(2) joo-al, two syllables, neutral vowel in second
(3) joo-ll, two syllables, second being syllabic consonant
(4) jua-l, single syllable, diphthong

I probably say jua-l, going towards jool in quick speech. When adding syllables the neutral vowel is further reduced to zero: jool-a-ri; but there is also the possibility of reducing the added -ar to zero vowel, thus jua-lri, which I might be inclined to say if I was being more careful. I think the underlying pronunciation is ju-al-ar-i with two neutral vowels, one of which has to go.

The non-US spelling is jewellery.

Actually in the popular speech round here, r becomes w as does postvocalic l, so it would be ju-w-wi.