Metamorphic rock textures: tectonic breccia, with fractures, veins, and angular fragments
In a slab of decorative building stone.
Pressure within the Earth fractured the dark rock, with fractures forming an angular framework. Fluid(s) invaded the rock along the fractures, and minerals precipitated from the fluid to form the light coloured greenish veins. Large (approx. 10 cm) dark pieces of the host rock can be seen 'caught in the act' of fracturing into smaller pieces, with the forms of the pieces fitting together in jigsaw fashion. Small dark pieces can be seen 'floating' in the matrix of the green vein material. Multiple stages of veins are present: later narrow white veins cut across earlier and larger greenish veins.
During my decades of past work as a geologist, I occasionally worked on rocks like this (structurally complex breccias and veins with brittle textures).
Copyright J.R. Devaney
Metamorphic rock textures: tectonic breccia, with fractures, veins, and angular fragments
In a slab of decorative building stone.
Pressure within the Earth fractured the dark rock, with fractures forming an angular framework. Fluid(s) invaded the rock along the fractures, and minerals precipitated from the fluid to form the light coloured greenish veins. Large (approx. 10 cm) dark pieces of the host rock can be seen 'caught in the act' of fracturing into smaller pieces, with the forms of the pieces fitting together in jigsaw fashion. Small dark pieces can be seen 'floating' in the matrix of the green vein material. Multiple stages of veins are present: later narrow white veins cut across earlier and larger greenish veins.
During my decades of past work as a geologist, I occasionally worked on rocks like this (structurally complex breccias and veins with brittle textures).
Copyright J.R. Devaney