What is composed of altering bands of light and dark silicate minerals?

What is composed of altering bands of light and dark silicate minerals?

Family of silicate minerals containing varying amounts of aluminum, iron, magnesium, and calcium. Schist and gneiss often have tiny, glassy red garnet crystals. A coarse-grained, foliated metamorphic rock that commonly has alternating bands of light and dark-colored minerals.

What type of rock has a characteristic of alternating mineral bands?

Gneiss forms at higher temperatures and pressures than schist. Gneiss nearly always shows a banded texture characterized by alternating darker and lighter colored bands and without a distinct cleavage. Gneisses are common in the ancient crust of continental shields.

Which of the following is a dark silicate?

The dark silicates are also called ferromagnesian because of the presence of iron and magnesium in them. They include olivine, pyroxene, amphibole and biotite. The light-colored silicates include quartz, muscovite and feldspar.

What is a non foliated metamorphic rock composed of calcite?

Non-foliated metamorphic rocks include quartzite, which is metamorphosed sandstone in which the quartz grains have recrystallized into a very solid interlocking network, and marble, which is metamorphosed limestone composed of recrystallized and interlocking calcite or dolomite crystals.

Which common mineral is composed entirely of silicon and oxygen?


Question Answer
What mineral is the hardest known substance in nature? diamond
Which carbonate mineral reacts readily with cool, dilute hydrochloric acid to produce visible bubbles of carbon dioxide gas? calcite
Which common mineral is composed entirely of silicon and oxygen? quartz

What are bands in metamorphic rocks?

Banding means that the rock consists of alternating, thin layers (typically 1 mm to 1 cm) of two different mineral compositions. Normally, the two types of layers have the same kinds of minerals, but in different proportions, giving the rock a striped appearance. Banding, by itself, defines a foliation.

What metamorphic rock contains bands?

Gneiss is a foliated metamorphic rock that has a banded appearance and is made up of granular mineral grains. It typically contains abundant quartz or feldspar minerals.

In what way are the dark silicate minerals different from the light silicate minerals?

(ferromagnesian) silicates, and list four common minerals from each group. The main difference between the light and dark silicates is their relative specific gravities (densities); light silicates are less dense (lower specific gravity) than the dark silicates.

What are dark minerals?

The abundant dark-coloured minerals include olivine, pyroxene, amphibole, biotite, garnet, tourmaline, iron oxides, sulfides, and metals. Most minerals fall within these two broad groups.

What is a foliated rock with gneissic banding composed of feldspar mica and quartz?


Texture Characteristics Rock Name
foliated (banded) thin layers of mica Schist
foliated (banded) thick layers of quartz, feldspar, and mica Gneiss
non-foliated (massive) welded quartz sandstone Quartzite
non-foliated (massive) sugary to course crystals, fizzes in HCl acid Marble