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Pegmatite. A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than 1 cm (0.4 in) and sometimes greater than 1 meter (3 ft). Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite.
Lepidolite is associated with other lithium-bearing minerals like spodumene in pegmatite bodies. It is the major source of the alkali metal rubidium. [13] In 1861, Robert Bunsen and Gustav Kirchhoff extracted 150 kg (330 lb) of lepidolite to yield a few grams of rubidium salts for analysis, and therefore discovered the new element rubidium. [14 ...
Miarolitic cavity. Miarolitic cavities (or miarolitic texture) are typically crystal-lined irregular cavities or vugs most commonly found in granitic pegmatites, and also in a variety of igneous rocks. The central portions of pegmatites are often miarolitic as the pegmatite dike crystallizes from the outside walls toward the center.
The Tin Mountain pegmatite is an igneous intrusion located in the southern Black Hills, South Dakota. It is a part of the Harney Peak Granite dome that formed in the Late Paleoproterozoic around 1.7 billion years ago. [ 1][ 2][ 3] The Harney Peak Granite system includes thousands of pegmatites, one of which is the Tin Mountain. [ 1]
Granite (light) with sheeted veins of greisen (dark) at Cligga Head, Cornwall. Greisen is a highly altered granitic rock or pegmatite, usually composed predominantly of quartz and micas (mostly muscovite). Greisen is formed by self-generated alteration of a granite and is a class of moderate- to high-temperature magmatic-hydrothermal alteration ...
Petalite. Petalite, also known as castorite, is a lithium aluminum tektosilicate mineral Li Al Si 4 O 10, crystallizing in the monoclinic system. Petalite occurs as colorless, pink, grey, yellow, yellow grey, to white tabular crystals and columnar masses. It occurs in lithium-bearing pegmatites with spodumene, lepidolite, and tourmaline.
Orthoclase, or orthoclase feldspar (endmember formula K Al Si 3 O 8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture", because its two cleavage planes are at right angles to each other. It is a type of potassium feldspar, also known as K-feldspar.
Amblygonite (/ æmˈblɪɡəˌnaɪt /) is a fluorophosphate mineral, (Li,Na)AlPO4(F,OH), composed of lithium, sodium, aluminium, phosphate, fluoride and hydroxide. The mineral occurs in pegmatite deposits and is easily mistaken for albite and other feldspars. Its density, cleavage and flame test for lithium are diagnostic.