Anthracite and it is found most abundantly in areas that have been subjected to considerable stresses and pressures, such as the flanks of great mountain ranges. Anthracite is associated with strongly deformed sedimentary rocks that were subjected to higher pressures and temperatures (but short of metamorphic conditions) just as bituminous coal is generally associated with less deformed or flat-lying sedimentary rocks. For example, the compressed layers of anthracite that are deep mined in the folded Ridge and Valley Province of the Appalachian Mountains of the Coal Region of East-central Pennsylvania are extensions of the same layers of bituminous coal that are
Anthracite budgerigar mutation two factors will deepen the body colour even more. Anthracite budgerigar mutation The Anthracite budgerigar mutation is an extremely rare mutation that occurs in the budgerigar. The mutation, similar to the Violet budgerigar mutation, causes a difference in the coloring of budgerigars. Anthracites have black or very dark gray feathers, possibly with some white depending on the budgerigar in particular. The mutation is believed to have started in Germany, and tends to be local to that area. Currently, most owners wishing to obtain an Anthracite need to import these budgerigars from Germany. The description and genetic behaviour of the Anthracite