What does hornsfels look like?

The hornfels facies is the metamorphic facies which occupies the lowest pressure portion of the metamorphic pressure-temperature space. The most common hornfels (the biotite hornfels) are dark-brown to black with a somewhat velvety luster owing to the abundance of small crystals of shining black mica.

1. How do you identify a hornfels rock?
2. How do you describe the texture of hornfels?
3. What is a hornfels how is it formed?
4. Where do you find hornfels?

How do you identify a hornfels rock?

Texture - granular, platy or elongate crystals randomly oriented so no foliation evident. Grain size - very fine grained; grains need to be observed under a microscope; can contain rounded porphyroblasts. Hardness - hard (commonly displays conchoidal fracture).

How do you describe the texture of hornfels?

Hornfels are medium to coarse crystalline rocks, dark color and rich in silicates with granoblastic and porphyroblastic texture.

What is a hornfels how is it formed?

All of the rocks called hornfels—a hard, fine-grained, flinty rock—are created when heat and fluids from the igneous intrusion alter the surrounding rock, changing its original mineralogy to one that is stable under high temperatures.

Where do you find hornfels?

In Africa, hornfels is found in Tanzania, Cameroon, East Africa, and Western Africa. The rock is found in Australia and New Zealand, as well.