Troctolite Rock - All you need to know

The term troctolite seems unfamiliar even in the (general) construction industry, homeowners, and contractors. Troctolite is a Geo-Science term. I think Gabbro rock may sound a familiar word for you, and Troctolite is a similar kind of intrusive. Igneous rock.

Here, intrusive means the rock forms when magma or molten lava is gradually cooling on the surface of the earth and forms large crystals in the rock. If the formation process is rapid and results in smaller crystals, it creates extrusive types of igneous rocks.

What Is Troctolite? 

Troctolite is coarse-grained and consists of predominantly Olivine & Plagioclase Feldspar. 

• Olivine is an influential rock-forming group of minerals containing Magnesium, iron silicates. It has unusual yellow to bottle-green tints due to Mg-Fe combinations in a series. 
• Plagioclase is a member of feldspar minerals forming translucent crystals. 
• When Olivine completely altered to serpentine, it results in a stippled appearance of green, brown, red, yellow, and black spots on the pale background. 
• According to Britannica, the appearance resembles the skin of trout (Troctolite in German), and famously "Trout Rock" in colloquial language.

Occurrence of Troctolite

According to Wikipedia, Troctolite found:

• The Archean Windimurra intrusion of Western Australia.
• The Voisey's Bay (nickel-copper-cobalt magmatic sulfide deposit) of northern Labrador.
• The Stillwater igneous complex of Montana.
• The Duluth Complex of the North American Midcontinent Rift.
• The Tertiary Rhum layered intrusion of the island of Rùm, Scotland.
• The Merensky Reef of the Bushveld Igneous Complex, South Africa.

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