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Epidosite

Epidosite is a highly altered epidote and quartz bearing rock. It is the result of slow hydrothermal alteration or metasomatism of the basaltic sheeted dike complex and associated plagiogranites that occurs below the massive sulfide ore deposits which occur in ophiolites.

Colors It Comes In - Green, apple green, grey, brown, or nearly black.

Fracture Pattern - Uneven or irregular.

Shape -

Interstitial pores:

Large, angular pores that are less than 500 micrometers in diameter. The walls of these pores have coarse crystal faces that give them their angular shape.

Crack shapes:

Epidosite has more variable crack shapes than diabase.

Spheroidal pores:

These pores are mainly found in the epidote-rich domains.

Euhedral epidote crystals:

These crystals have grown inward into the interstitial pores.

Luster - vitreous to resinous

Texture - Epidosite is a metamorphic rock that lacks its original igneous texture (sandpaper like).

Where They Can Be Found -

Sub-seafloor hydrothermal systems:

Epidosite can form in these systems when chemically altered seawater reacts with basalts, gabbros, and plagiogranites. Active submarine spreading ridges, Submarine extensional structures.

Ophiolites:

Epidosite can be found in the upper extrusive layers of ophiolites, such as the Pindos, Othris, Josephine, Solund-Stavfjord, and Miaowan. Cyprus: Epidosite in Cyprus is believed to be the result of a phreatic eruption.

Hardness On The Mohs Scale - 6 To 7 Out Of 10

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