Leçon :
Définition : Le Quartz est un minéral du groupe des silicates. Il se présente sous la forme de grands cristaux incolores, colorés ou fumés. Constituant à 12 % (en masse) de la lithosphère, le quartz est le minéral le plus commun de la croute terrestre (l'oxygène et le silicium sont respectivement les premier et deuxième constituant de la lithosphère, par ordre d'importance). C'est une composante importante du granite et des granitoïdes où il est généralement xénomorphe, des roches métamorphiques granitiques (gneiss, quartzite) et de certaines roches sédimentaires (sable, grès).
Histoire : Les Grecs de l'Antiquité pensaient que les cristaux de quartz étaient de la glace si dure qu'elle ne fondait pas. Ils les appelaient « krystallos », leur mot pour glace, à l'origine du mot « cristal ». Les cristaux de quartz étaient en réalité les premiers « cristaux ».
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With Flo, we share a great passion for geocaching: EarthCaches 🥰. We are intense rock hunters! 🪨😄 You could even say it’s a real crush 🤢. Our second geocaching passion is GeoArt 🤩. So we pushed ourselves a bit and decided to mix the two. A big headache to set up 😵, but in the end, totally doable.
Questions : Locate the blue dot in the photo above and answer the following:
1 - What other mineral, usually xenomorphic, is it a component of ?
2 - Based on your observation, what is the color of this quartz ?
3 - Is it rather light, translucent, or smoky ?
4 - Take a photo in front of this wall (without the quartz), with your geocaching username visible, and make a 🤘 sign with your hand.
EarthCache Rules: "Log this "Found it" cache and send me your suggested answers either via my profile or via email, and I will contact you if there is a problem."
Lesson :
Definition : Quartz is a mineral belonging to the silicate group. It occurs as large, colorless, colored, or smoky crystals. Constituting 12% (by mass) of the lithosphere, quartz is the most abundant mineral in the Earth's crust (oxygen and silicon are the first and second most abundant minerals in the lithosphere, respectively). It is a significant component of granite and granitoids, where it is generally xenomorphic, as well as granitic metamorphic rocks (gneiss, quartzite) and certain sedimentary rocks (sand, sandstone).
History : The ancient Greeks believed that quartz crystals were ice so hard that it did not melt. They called them "krystallos," their word for ice, which is the origin of the word "crystal." Quartz crystals were, in fact, the first "crystals."
Happy Géocaching everyone 😎