Noldorin
malthen
adjective. of gold, of gold [metal]
malthen
adjective. of gold, golden
mallen
adjective. of gold
mallen
adjective. of gold, golden
malt
noun. gold (as metal)
côl
noun. gold (metal)
glaur
noun. gold
gloriel
adjective. golden
An adjective in The Etymologies of the 1930s glossed “of gold” based on N. malt “gold (as metal)” under the root ᴹ√SMAL “yellow” (Ety/SMAL). The form was revised to (h)malthen indicating an archaic voiceless hm that was the result of ancient sm (EtyAC/SMAL), but in Tolkien’s later writings the root became √MALAT (PM/366) so this would no longer be the case.
Neo-Sindarin: In Sindarin of the 1950s and 60s, medial lth became voiceless ll (VT42/27), as seen in the noun mallorn “gold tree” and (probably) the later adjective mallen “golden”. However Tolkien said:
> ... among those to whom Sindarin became a language of lore, as the men of Gondor who were or claimed to be of Numenórean race, the spirant [th] was reintroduced from the spelling. In true Sindarin of the Elves or Elf-friends of the early ages the final form [lt] was often introduced medially (VT42/27).
As such, I think malthen “of gold [metal]” may still be viable by analogy with its noun form malt “gold [metal]”, and the adjective mallen may be limited just to golden colors.
Conceptual Development: The Gnomish Lexicon of the 1910s had similarly formed G. maltha “golden yellow, rich, mellow” (GL/56) likely based on the early root ᴱ√MALA “yellow” (QL/63).