now the noldoli that laboured in the earth and aforetime had skill of crafts in metals and gems in valinor were the most valued of the thralls of melko , and he suffered them not to stray far away , and so it was that beleg knew not that these elves had little lanterns of strange fashion , and they were of silver and of crystal and a flame of a pale blue burnt forever within , and this was a secret and the jewel-makers among them alone knew it nor would they reveal it even to melko , albeit many jewels and many magic lights they were constrained to make for him .