Chemistry: various crystalline substances. Coloured engraving. https://www.rawpixel.com/image/13951393/chemistry-various-crystalline-substances-coloured-engravingFree Image from public domain licenseGeology: various crystalline substances. Coloured lithograph by A. Pralon after G. Pouchet. https://www.rawpixel.com/image/13969361/image-art-football-soccer-ballFree Image from public domain licenseVariety of colorful natural stones. Free public domain CC0 photo. https://www.rawpixel.com/image/6037453/photo-image-public-domain-black-background-redFree Image from public domain licenseThe eclectic guide to health; or, Physiology and hygiene (1887), vintage human brain illustration. Original public domain… https://www.rawpixel.com/image/11066661/image-face-plant-medicineFree Image from public domain licenseStill Life with Ostrich Egg Cup and the Whitfield Heirlooms by Pieter Gerritsz. van Roestraeten https://www.rawpixel.com/image/8962702/image-person-art-coralFree Image from public domain licenseSeven pieces of tufa from the vicinity of Naples. Coloured etching by Pietro Fabris, 1776. https://www.rawpixel.com/image/13959052/image-person-art-black-backgroundFree Image from public domain licenseVariety of colorful natural stones. Free public domain CC0 photo. https://www.rawpixel.com/image/6037450/photo-image-public-domain-black-background-redFree Image from public domain licenseEffects of Alcohol upon the brain of a boy seventeen years of age. The whole organ and its membranes and vessels were… https://www.rawpixel.com/image/9975838/image-face-person-artFree Image from public domain licenseSix pieces of lava from inside the crater of Mount Vesuvius. Coloured etching by Pietro Fabris, 1776. https://www.rawpixel.com/image/13964993/image-art-black-background-public-domainFree Image from public domain licenseEight pieces of volcanic matter taken from the road leading from the Pisciarelli (spring) to the Solfatara. Coloured etching… https://www.rawpixel.com/image/13951821/image-art-black-background-roadFree Image from public domain licenseGarniture of Three Vases (vases des âges) by Jacques François Deparis, Etienne Henry Bono, Antoine Caton, Etienne Henri Le… https://www.rawpixel.com/image/14264563/photo-image-face-trophy-personFree Image from public domain licenseSnuff bottle. Pink agate. Crystal top. Carved lotus design.. Original from the Minneapolis Institute of Art. https://www.rawpixel.com/image/7656021/photo-image-vintage-art-public-domainFree Image from public domain licensesnuff bottle, rutile (hair crystal). Original from the Minneapolis Institute of Art. https://www.rawpixel.com/image/7655680/photo-image-vintage-art-public-domainFree Image from public domain licenseScaraboid: Thoth as a Baboon with Lunar Crescent by Ancient Egyptian https://www.rawpixel.com/image/9042639/scaraboid-thoth-baboon-with-lunar-crescent-ancient-egyptianFree Image from public domain licenseScarab: Usermaatra Setepenra (Ramesses II) by Ancient Egyptian https://www.rawpixel.com/image/9050454/scarab-usermaatra-setepenra-ramesses-ii-ancient-egyptianFree Image from public domain licenseSnuff Bottle with Scholar and Assistant on Rocky Promontory https://www.rawpixel.com/image/8955951/snuff-bottle-with-scholar-and-assistant-rocky-promontoryFree Image from public domain licenseMineral stone png illustration, transparent background. Free public domain CC0 image. https://www.rawpixel.com/image/7595952/png-people-patternFree PNG from public domain licenseAgate Exhibit at Cape Perpetua Visitors Center, Siuslaw National Forest. Original public domain image from Flickr https://www.rawpixel.com/image/4075942/photo-image-flower-light-plantFree Image from public domain license