This pioneering work contains a very early example of Garnier’s photogravure process from photographs of crystals. Duc de Luynes participants Garnier et Salmon from Chartres sought to express how their versatile brass-plate reproductive process could be used to make prints from all three printmaking idioms: relief, intaglio, and planographic. In the summer of 1859, they submitted to the jury a few published examples made by their process including a multi-image plate showing quartz cross-sections. The heightened attention to surface, texture, and materiality in the work of Garnier et Salmon signal a desire among participants in the contest for their printed images to serve as both examples of their process and signs of the process itself. 
While Garnier’s name appears throughout the French and British photographic literature of the late 1850s to late 1860s, it is mentioned infrequently at best in the modern historiography of the medium. He deserves to be better known. His accomplishments are numerous, and striking: he developed a proprietary photographic engraving process with Alphonse Salmon, based on the light sensitivity of iron salts, which the pair discovered; created some of the finest photogravures of his age, for which he won the grand prix for photography at the 1867 Exposition universelle and was a finalist in the Duc de Luynes competition; and pioneered the steel-coating of copper printing plates (which he called “aciérage”), which dramatically improved their strength and durability and was widely adopted in the nineteenth century. 
"After much trial and error attempting to obtain durable copies of the most of the phenomena produced by various varieties of quartz viewed under polarized light, I opted for the process by Messrs Salmon and Gamier of Chartres as offering the greatest chances of success. The process produces, without any reworking, an intaglio metal plate, by means of glass positives, produced with the original negatives, and which can be printed off by ordinary intaglio methods. Unfortunately, this heliographic engraving has so far failed to retain all the subtleties and sharpness of photography, but it at least satisfies the painstaking accuracy of detail that, impressed by light, can then be transferred onto properly prepared metal plates." 
Hanson, David A. Checklist of Photomechanical Processes and Printing, 1825-1910. , 2017. p. 55.
 “Mémoire sur la cristallisation et la scructure intérieure du quartz,” Annales de chimie et de physique 45 (October 1855) pp.129-315.
 On Garnier, see Meizel, “Inventer, ” 701–04.
 Hanson, David A. Checklist of Photomechanical Processes and Printing, 1825-1910. , 2017. (translation by Steven F. Joseph) p. 56