Microscopes can show the different types of cement pore-fillers in carbonate rocks.
Carbonate rocks are in the class of sedimentary rocks and composed primarily of carbonate minerals. While primarily made from carbonate minerals, these rocks also have microfacies -- compositions, features or appearances of a rock or mineral in a thin section that are only visible under a microscope. Microfacies show where spaces or voids are filled with pore-filling cements for the different types of carbonate rocks. Pore-filling cements are classified by a shape based on a crystal relation in a length to width ratio.
Silicates
Silicates are silicon dioxide (SiO2). Silicates fillers in the rock present themselves in a variety of colors including dull gray, yellow, white, off-white or black. Formations of silicates include coarse blocky spar quartz; radiating bundles of needles; chalcedony, which is a milky or grayish translucent to transparent quartz; irregular microcrystalline, which contains crystals that are visible only under a microscope; and blocky chert, which are rock fragments.
Anhydrite
Anhydrite is calcium sulfate (CaSO4) and is coarse and fibrous. Anhydrite is typically converted to gypsum -- hydrated calcium sulfate, which in colorless and odorless.
Hemetite
Hemetite is iron sulfate (FeSO4) and can be dense in color, dark reddish, translucent or almost opaque. Colors are microcrystalline.
Celestite
Celestite is the sulfate salt of strontium (SrSO4). Celestite is characterized as having a light bluish color. The strontium in celestite is released from recrystallizing unstable aragonite. Celestite appears in supratidal cementation -- a marginal zone in the act, process or result of cementing -- and evaporites, sedimentary deposits that result from the evaporation of seawater.
Calcium Carbonate
Calcium carbonate (CaCO3) is classified by crystal size. There are three main sizes for CaCO3: microcrystalline cement, which is more than four microns; micro spar, 5 to 30 microns; and spar, less than 30 microns.
Related posts
A thin slice of agate reveals crystals inside.Gems, minerals and precious stones all come in crystalline forms that offer visual appeal. When choosing such stones for personal use, your own taste...
Southeast Tennessee is a source for several types of rocks.Southeastern Tennessee includes the counties of Franklin, Grundy, Marion, Hamilton, Bledsoe, Sequatchie, Rhea, Meigs, McMinn, Bradley and...
Rock carving has been part of different cultures around the world.Carving into rock used to be a way for people to communicate with each other, tell stories and maintain history. Now rock carving...
Rocks are made up of minerals.Depending on their origin, rocks are classified into three groups: igneous, metamorphic and sedimentary. Sedimentary rocks form through slow deposition, burial and co...
The three basic types of rocks are igneous, sedimentary and metamorphicAll of the rocks on earth can be classified into three categories: igneous, metamorphic and sedimentary. Igneous rocks are cr...
