Why are there different types of quartz specimens yet they all have the same chemical formula Si02?
2007-11-01 16:04:45 · 3 answers · asked by Gideon 1 in Science & Mathematics ➔ Earth Sciences & Geology
1/ There are different variety of quartz depending of the inclusions, modification of crystalline framework and impurities within. Here is a list of variety with the reason :
- Pink : massive it is due to traces of iron, manganese or titanium. The asterism (shape of a star when polished) is due to small fiber of dumortierite, a mineral. When crystallized, the pink quartz coloration is rather due to phosphate ( like in some Paris Basin quartz) or aluminium.
- Amethyst : Maybe be manganese but some believe it could be organic, iron or even aluminium.
- Citrine : iron
- Aventurine : inclusion of green mica (fushite)
- Tiger's eye : inclusion of fiber of silicified crocidolite (variety of asbestos)
- Prasiolite : Iron or copper
- Milk quartz : gas and liquid inclusions
- Smoky : Radioactivity on quartz containing aluminium
- Blue : pressure.
- Chalcedony is a variety of quarz with micro-crystals. Agate is a multicolor variety of chalcedony and onyx is a variety of agate with parallel strips of various nuances of black.
2/ In addition, there are different variety of silicae which are depending on pressure and temperature, like trydimite and cristobalite (high temperature), coesite (high pressure), stiskhovite (higher pressure even) etc...
2007-11-01 23:45:25 · answer #1 · answered by omalinur 4 · 0⤊ 0⤋
Mostly because of impurities in the crystal lattice (iron, titanium, cobalt, etc.)
Other reasons include temperature of formation (tridymite, coesite) and differences in crystallization (macrocrystalline, cryptocrystalline, microcrystalline)
2007-11-01 23:08:31 · answer #2 · answered by Lady Geologist 7 · 2⤊ 0⤋
its the way the chains are put togethor, thats what seperates diamond from coal.
2007-11-01 23:06:30 · answer #3 · answered by wazzacky66 2 · 1⤊ 1⤋