Actinolite

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Actinolite - from sea shell to needle

Let the rocks tell their story

story under development...
I started my life as a sea shell in a warm ancient shallow sea. When I died my shell joined many others in the ooze at the bottom of the sea.
Layers and layers of ooze built up and the weight of the ooze above forced the water out and I slowly turned into a rock called limestone.
Time passed and the limestone was pushed up and became land.
Time passed until hot rocks from deep beneath the earth rose up and cooked me at a low temperature so that my crystals grew bigger, denser and needle-like and any visible evidence of sea shells disappeared.



Scientific explanation:
Actinolite  Ca2(Mg,Fe)5Si8O22(OH2
The contact aureoles produced in siliceous limestones and dolomites, called skarns or calc-silicate rocks, characteristically contain metamorphic amphiboles such as tremolite or actinolite. The presence of tremolite implies a relatively low grade of metamorphism as tremolite breaks down to form the pyroxene diopside in the presence of calcite and quartz at elevated temperatures. Richterite-winchite occurs in hydrothermally metamorphosed limestones. Magnesium-rich anthophyllites are found along contact zones of granitic dikes intruding ultramafic rocks (those rich in iron and magnesium).