Clinochlore


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clinochlore

[′klī·nə‚klȯr]
(mineralogy)
(Mg,Fe,Al)3(Si,Al)2O5(OH)4 Green mineral of the chlorite group, occurring in monoclinic crystals, in folia or scales, or massive.

Clinochlore

 

a mineral of the chlorite group; one of the layered aluminosilicates.

The approximate chemical composition of chlinochlore is

(Mg, Fe)4.75 Al,1.25 [Al,1.25 Si2.75 O10] (OH)8

The ratios of magnesium to aluminum and aluminum to silicon vary considerably, although clinochlore is primarily a magnesium-aluminum chlorite. The low-iron variety of clinochlore is known as leichtenbergite (colorless). Clinochlore containing admixtures of chromium is called kotschubeite (pinkish-violet).

Clinochlore crystallizes in the monoclinic system, forming small pseudohexagonal plumose crystals with good cleavage. Most often, clinochlore forms microplumose aggregates. Its color ranges from dark gray-green to light olive-green. Clinochlore is transparent in the form of thin laminae. Its hardness on the mineralogical scale is 2–2.5; its density varies between 2,610 and 2,780 kg per cu m. It is a rock-forming mineral in chlorite shales and occurs in other metamorphic rocks as well (appearing as a result of changes in pyroxenes, amphiboles, garnets, ferromagnesian mica). Clinochlore also exists in contact-meta-somatic rocks, such as skarns, and in modified secondary rocks in hydrothermal lodes. Clinochlore is very widely distributed in nature.

G. P. BARSANOV

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Castellanos and co-workers (personal communication) described in detail the characteristic mineral assemblages from reaction zones recognized in marbles, which include calcite + graphite [+ or -] quartz; calcite + diopside [+ or -] tremolite [+ or -] epidote-group minerals [+ or -] muscovite; calcite + wollastonite + quartz + garnet + diopside; calcite + dolomite + Ti-clinohumite + diopside + forsterite + clinochlore [+ or -] graphite; calcite + forsterite + tremolite; dolomite + calcite + clinochlore.
the Keystone Trappe Rock quarry at Cornog (exquisite small specimens of Alpine-type cleft minerals), Brinton's quarry at Darlington's Corners (the world's best large clinochlore crystals), the Poorhouse quarry, West Bradford Township (excellent microcline), Corundum Hill, Newlin Township (good corundum and superb diaspore crystals), the fields around Parkesburg where line rutile crystals may still be found loose in the soil.
5 350 Equilibria E1 6 Mg-Al-celadonite + 1 amesite = 2 clinochlore + 6 K-feldspar + 2 quartz + 2 H2O E2 4 Mg-Al-celadonite + 2 muscovite = 6 K-feldspar + 1 amesite + 2 quartz + 2 H2O E3 5 Mg-Al-celadonite + 1 muscovite = 1 clinochlore + 6 K-feldspar + 2 quartz + 2 H2O E4 3 Mg-Al-celadonite = 1 phlogopite + 2 K-feldspar + 3 quartz + 2 H2O IP1 intersection of 6 equilibria with the subsequent participating mineral components: Mg-Al-celadonite, muscovite, phlogopite, clinochlore, K-feldspar, quartz, H2O
The major mineral composition for Lahore soil is Quartz, Muscovite and Clinochlore, which shows that the alluvial deposit received sediments from metamorphic origin.
2+] -rich trioctahedral chlorites, namely clinochlore and chamosite, and the Al-rich dioctahedral species, donbassite.
Lawrence County, New York and clinochlore from West-townr Chester County, Pennsylvania.
Mineralogists of the 19th century were much more successful in the description of new layer hydrosilicates: allophane, amesite, antigorite, aspidolite, batavite, biotite /a series name/, celadonite, chamosite, chrysotile /a series name/, clinochlore, corundophyllite, cronstedtite, delessite, diabantite, ephesite, glauconite /a series name/, halloysite, kaolinite, muscovite, nacrite /a polytype/, nontronite, palygorskite, paragonite, penninite /or pennine/, phengite /a series name/, phlogopite, polylithionite, pyrophyllite, ripidolite, roscoelite, saponite, sauconite, sepiolite, serpentine, siderophyllite, stevensite, tainiolite, thuringite, vermiculite /trioctahedral and dioctahedral, distinguished in the 20th century/, volkonskoite, zinnwaldite /a series name/.
These two mines were the source of the "colerainite" variety of clinochlore (named for the nearby town of Coleraine; Black Lake was in the Municipality of Coleraine at the beginning of 1900).
And clinging to some of Laurent's garnets is an association I'd never seen before: sharp, fat, dull green books of clinochlore to 3 cm.
Typical minerals of the quartz veins and their cavities include albite, fluorapatite, calcite, chabazite, clinochlore, dolomite, goethite, graphite, kaolinite, muscovite, molybdenite, pyrite, pyrrhotite, quartz, rutile, siderite and tourmaline.
Only one locality produces high-quality clinochlore containing enough chromium to turn the crystals cherry-red to purple.