الإثمد
A dark mineral powder (antimony-based in classical use) applied to the eyes, recommended as a nightly practice said to strengthen sight and grow the eyelashes.
عَلَيْكُمْ بِالْإِثْمِدِ عِنْدَ النَّوْمِ، فَإِنَّهُ يَجْلُو الْبَصَرَ وَيُنْبِتُ الشَّعْرَ
“Use ithmid kohl before sleeping, for it sharpens the eyesight and helps the lashes grow.” (meaning, not a literal translation)
Ibn al-Qayyim describes ithmid as drying and cleansing to the eye, best applied at night when the eye is at rest.