Only in plural, from an unused root meaning to be hard; ebony -- ebony.
H1894. hobni
[הָבְנִי] noun [masculine] ebony (so Symm ᵑ9 Ki & moderns; otherwise ᵑ6 ᵐ5; Egyptian heben, LiebleinÄZ 1886, 13 compare PinskEinleitung 83; Greek ἔβενος, Latin hebenum) — only plural הָבְנִים Ezekiel 27:15 Qr (Kt הובנים) והבנים שֵׁן קַרְנוֺת; it was brought from India, & (finer) from Ethiopia, compare Sm & references