Answer:

eosin

AnswerCrossword Clue
EOSINDye used in some ballpoint ink
EOSINCertain red dye
EOSINCosmetics dye
EOSINRose-red dye
EOSINBiology lab stain
EOSINRed dye
EOSINRed stain in a lab
EOSINDye chemical
EOSINBiological stain
EOSINLab stain