Spectrum Chemical manufactures and distributes fine chemicals with quality you can count on including those with CAS number 6151-25-3, Whether you call it Quercetin, Dihydrate, 3 -3 -4 -5 -7-Pentahydroxyflavone or 2-(3 -4-Dihydroxyphenyl)-3 -5 -7-trihydroxy-4H-1-benzopyran-4-one you can be assured the Quercetin, Dihydrate products offered by Spectrum, meet or exceed the grade requirements or specifications for each individual product.