A note on the use of crystal engineering to increase the opacity of terra verde inpainting pigment: Adulteration of green earths

An integrated analytical approach for the characterization of repainted wooden statues dated to the fifteenth century

“…Since their introduction in the XX century (and precisely in 1936 [50]) blue and green phthalocyanines are among the most used pigments. Among these PG7 and PG36 green colorant [48,49,50] and also copper phatalocyanine CuPc [51] show signals in the same spectral range as our sample but a more precise identification is not possible (some of the spectra of other green colorants belonging to the same group are not published, at least to our knowledge).…”

High-resolution non-invasive X-ray diffraction analysis of artists’ paints

“…Green earth most commonly contains the natural green clay minerals glauconite and celadonite [6] but there are exceptions [85] and modern varieties may be adulterated with synthetic organic greens [86].…”