Probably from chalam (in the sense of hardness); flint -- flint(-y), rock.
see HEBREW chalam
H2496. challamish
חַלָּמִישׁ noun masculine flint; — חַלָּמִישׁ Deuteronomy 8:15 3t.; construct חַלְמִישׁ 32:13; — flint הַח ׳צוּר rock of flint = flinty rock, whence water flowed for Israel in desert 8:15, and (no צור) Psalm 114:8; worked by miners Job 28:9; hyperb. oil out of ׳ח צוּר Deuteronomy 32:13 flint of rock = rocky flint (poetry); — in simile of firmness כַּחַלָּמִישׁ מָּנַי שַׂמְתִּי עַלכֵּֿן Isaiah 50:7.
חֹלוֺן חֵלֹן, see below I. and II. חוֺל.