1 Used other than as an idiom: see outer ,â core. ( 2 planetology) The hot liquid material found near the centre of some planets, distinct from the solid inner core. ( 3 geology) The part of the Earth between the mantle and inner core, responsible for generating the planet's magnetic field. 4  Link/Cite.
Differential Staining is a staining process which uses more than one chemical stain. Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism.
Gram staining is a differential staining technique that differentiates bacteria into two groups: gram-positives and gram-negatives. The procedure is based on the ability of microorganisms to retain color of the stains used during the gram stain reaction. Gram-negative bacteria are decolorized by the alcohol, losing the color of the primary stain, purple. Gram-positive bacteria are not decolorized by alcohol and will remain as purple.