@prefix qx8: <http://data.loterre.fr/ark:/67375/QX8> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .

qx8:-VGMZFRM2-Z
  skos:prefLabel "minéral"@fr, "mineral"@en ;
  a skos:Concept ;
  skos:narrower qx8:-SHM4L420-F .

qx8:-SHM4L420-F
  skos:definition "Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at 573 °C (846 K; 1,063 °F). Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Europe and Asia. Quartz is the mineral defining the value of 7 on the Mohs scale of hardness, a qualitative scratch method for determining the hardness of a material to abrasion. (Adapted from: <a href=\"https://en.wikipedia.org/wiki/Quartz\">https://en.wikipedia.org/wiki/Quartz</a>)"@en, "Le quartz est un minéral du groupe des silicates, sous-groupe des tectosilicates, composé de dioxyde de silicium, ou silice, de formule chimique SiO2, avec des traces de différents éléments tels que Al, Li, B, Fe, Mg, Ca, Ti, Rb, Na, OH. Il se présente sous la forme ou bien de grands cristaux incolores, colorés ou fumés, ou bien de cristaux microscopiques d'aspect translucide. Constituant 12 % (en masse) de la lithosphère, le quartz est le minéral le plus commun (l'oxygène et le silicium sont respectivement les premier et deuxième constituants, par ordre d'importance, de la lithosphère) ; c'est un composant important du granite, dont il remplit les espaces résiduels, et des roches métamorphiques granitiques (gneiss, quartzite) et sédimentaires (sable, grès). (Adapté de : <a href=\"https://fr.wikipedia.org/wiki/Quartz_(min%C3%A9ral)\">https://fr.wikipedia.org/wiki/Quartz_(min%C3%A9ral)</a>)"@fr ;
  skos:inScheme qx8: ;
  skos:exactMatch <https://en.wikipedia.org/wiki/Quartz>, <http://data.loterre.fr/ark:/67375/26L-JNR3219N-J>, <https://fr.wikipedia.org/wiki/Quartz_(min%C3%A9ral)> ;
  skos:broader qx8:-VGMZFRM2-Z ;
  skos:prefLabel "quartz"@fr, "quartz"@en ;
  a skos:Concept .

qx8: a skos:ConceptScheme .