It's the name of the color. See links:

wwwchem.uwimona.edu.jm/lab_manuals/c10expt25.htmlShareIn general, 0.5 - 1 g (or 0.5 - 1 mL) of substance gives the most satisfactory results. ... Place a piece of clean sodium metal, about the size of a pea into a fusion tube. ... Formation of a bluish-green precipitate (Prussian blue) or a blue solution .... acidify it cautiously to congo red with concentrated hydrochloric acid (added ...

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Our high quality range of Pea Green Lake is characterized by green color and is available in the powdered form. It is precisely formulated by our experienced ...