In need of a female name with specific meaning

I have been trying to figure out the most accurate female name that still sounds good meaning "the silver light of the moon and stars" in Sindarin. This name may or may not end up being my god-daughters name, so I'd really like not to get it wrong.

I think I've figured out the phrase itself: silith ithil ah elin (?)

But a name stumps me. Tolkein obviously created such a name: ithildin, which I really like the sound of. But, of course we know that this was the name of a special metal substance, and not therefore meant to be a person's name. Is it too silly to use it as is? Is there something that could be added or changed slightly that would make it better suited? Or should it simply be something origional and unrelated to this word all together?

Excited to learn more and hear all thoughts and corrections!

Welcome Sevyrance! For your sentence I would say:

i-Galad gelebrin en-Ithil a gîl. (The silver like light of the Moon and stars.) silith is (light of Silpion) which probably meant moonlight after it was lost.

It is up to you for a name Ithildinil/Ithildineth could be two possibilities for a female name.

If you have any other thoughts for names let me know.

Thanks so much for your response, Rínor!

Do you think Ithildinil/Ithildineth or anything containing 'ithildin' would still technically be referring to the metal? I worry that the words literal meaning gets overshadowed by it's correlation to the substance.

I also like the shorter more simple sound of just Ithildin. Does it require the endings to become a name or can it be a name on its own?

If we didn't use 'ithidin' at all, what else then might it be?

Yes, anything with “ithildin” would pertain to a magical alloy that glows in moonlight or (lit) moon-star. Although the star portion is from “tîn” is more like spark, sparkle, twinkle of stars. If you wanted to use “Ithildin” would be fine since it contains two elements.

Tolkien himself said: The mere names of things, such as “hill, river, tree”, and especially of unique things, as “sun”, were not used, at any rate without differentiation: [...] for that would imply some kind of total equation or identity. An Elf (or Man) would not be called Anar “Sun” even to depict great glory or radiant vigour. [...] But an Elf or Man could be called Anárion, Anardil [etc.] [PE21/86]

So another name you could do is Gilithil “star-moon. Celebringil would be “silver like star”