molten, melted (adjs.)

Molten is used primarily of liquid lava and metals liquefied by heat. Melted is used of snow and ice, butter and chocolate, and other common substances turned liquid by heat, and melted is usually the generic adjective as well. It is also used figuratively, as in Her heart melted at the sight of the puppy.

http://www.bartleby.com/68/30/3930.html

Webster's 1913 Dictionary

Definition: Mol"ten, a. [See {Melt}.]
1. Melted; being in a state of fusion, esp. when the liquid
state is produced by a high degree of heat; as, molten
iron.

2. Made by melting and casting the substance or metal of
which the thing is formed; as, a molten image.

http://www.hyperdictionary.com/dictionary/molten

Main Entry: mol·ten
Pronunciation: 'mOl-t&n
Function: adjective
Etymology: Middle English, from past participle of melten to melt
Date: 14th century
1 obsolete : made by melting and casting
2 : fused or liquefied by heat : MELTED <molten lava>
3 : having warmth or brilliance : GLOWING <the molten sunlight of warm skies -- T. B. Costain>

melt (verb)

intransitive senses
1 : to become altered from a solid to a liquid state usually by heat
2 a : DISSOLVE, DISINTEGRATE <the sugar melted in the coffee> b : to disappear as if by dissolving <her anger melted at his kind words>
3 obsolete : to become subdued or crushed (as by sorrow)
4 : to become mild, tender, or gentle
5 : to lose outline or distinctness : BLEND
transitive senses
1 : to reduce from a solid to a liquid state usually by heat
2 : to cause to disappear or disperse
3 : to make tender or gentle : SOFTEN

(Merriam-Webster)

Bin kein Muttersprachler, aber vielleicht hilft das schon mal ein bisschen weiter...