Siliceous rock characteristics

Diatomaceous earth is mainly composed of ancient diatom remains. The main chemical component is water-containing SiO2. The mineral component is mainly opal-A. Diatomaceous earth has a typical diatom biological structure with a fine texture. The pure diatomaceous earth is white, the appearance is earthy and easy to be broken into powder, soluble in alkali and not soluble in acid, strong in adsorption and high in melting point.

The sponge rock is mainly composed of siliceous sponge bone, and the mineral component is mainly opal. The appearance is fine-grained, grayish green or black, and the loose sponge rock is poorly cemented with clay and sand. The hard sponge rock is cemented with siliceous minerals such as opal and chalcedony, and is formed by the sea.

The radiolarian rock is mainly composed of siliceous radiolarian shell, which has the characteristics of light weight and hardness. The radiolarian shell in the hard radiolarian rock is completely oxidized by silica gel. Radiolarian soft mud is widely distributed mainly in modern tropical marine sediments.

The platy diatomaceous earth and protein soil mainly consist of angular or spheroidal opal points, most of which have a microporous structure and are produced by a lens body. The platy diatomaceous earth is powdery and lighter in color than sulfur. The proteinaceous soil is hard, shell-like fracture, darker in color, often dark gray or grayish black.

The main mineral component of jasperite is self-generated quartz, which can contain a small amount of biological remains, such as radiolaria, sponge bone and so on. Jasperite presents various colors due to the inclusion of iron oxide, often red, green or grayish yellow, giving the rock a variegated hue.

The meteorite is mainly composed of microcrystalline quartz and chalcedony. The lithology is dense and hard with a shell-like fracture. The color varies depending on the impurities. Pure vermiculite under the microscope is a colorless microcrystalline quartz aggregate. Vermiculite is formed in three different types of stratigraphic units: vermiculite nodules in carbonate rocks; layered vermiculite in stable areas; meteorites in super-salt lake environments.

A sedimentary rock formed by chemical or biochemical action with silica as the main rock-forming component. Also known as ochre rock. Generally, SiO2 is contained in an amount of 80% or more, and often more than 95%. The SiO2 mineral is not derived from debris, but is derived from the siliceous bones, shells or fragments of the organism, which are produced by direct precipitation or metabolization by chemical action. Volcanic activity increases the siliceous content of the ocean and is the main source of silicon in siliceous rocks. The main minerals in siliceous rocks are opal, chalcedony and authigenic quartz. Siliceous rocks have two major types of structures. One type is a biological structure in which radiobacteria, diatoms, or siliceous residues of siliceous algae can be seen under a microscope in a siliceous rock. The other type is a non-biological chemical precipitation structure. The primary precipitated siliceous material is generally an amorphous structure, but after diagenesis, the amorphous opal transforms into crystalline chalcedony and quartz, which becomes a crystalline structure. Siliceous rocks are divided into layered siliceous rocks and nodular siliceous rocks, as well as silty rocks that are irregularly replaced. Siliceous rocks are composed of siliceous shells, chemically precipitated, diagenetic tuberculosis and siliceous carbonate rocks. However, the enrichment of siliceous matter in seawater is often associated with siliceous matter from volcanic activity.