Know the "sea green stone"

It is a typical example of supergene minerals produced in shallow-water sediments (eg sandstones, carbonate rocks, etc.). In modern times, the depth of 300-500 meters in the depth of the sea sediments in the green silt and sand have also been found; in the North China Sea stratum is prolific in the Sinian, Cambrian, Ordovician strata, in Central and Southwest The Sinian is mainly produced in the Devonian strata; the glauconite is a potassic iron-rich mineral (Potassiumiron Silicate) and widely distributed in shallow-water sediments.

Summary

The chemical composition is K1-X(Al,Fe)2[Al1-XSi3+XO10](OH)2. The crystals are monoclinic delamination structure silicate minerals. The chemical composition is similar to that of mica. Compared to mica, the Al/Si value of the glauconite is smaller, the quantity of K is smaller, and the amount of Na substitution can be up to 0.5%. The content of K and Fe ions in the hailuite varies with the geological time and lithology of the output. Generally, the K2O content of the porphyrite produced by the Early Paleozoic is relatively high, and the output of the modern marine sediments is the chloroplasts. Higher Fe content. Fresh sea green stone is green, dark green, opaque. It has a leaf-like shape, a rounded granular shape, an irregular worm shape, a plate shape, and the like. Moss hardness of 2 to 3, brittle, with a specific gravity of 2.2 to 2.8. Aquamarine is used to treat water quality and improve soil. The processed sea green stone can adsorb Mg and Ca ions in water and release Na ions. In the treatment of water, it can be used to remove soluble iron and manganese salts from water. Can also be used as a pigment, glass polishing agent. There are different views on the origin of the sea-green stone, and most people think that the sea-green stone is formed under the conditions of a shallow sea environment with a depth of 100 to 300 meters, slow deposition, and the presence of montmorillonite. The chloroplast in the seabed is a typical marine sediment.

Mineral Name: Glaucite

Collection Location: China

Chemical composition: K1-x{(Fe3+,Al,Fe2+,Mg)2[Al1-xSi3+xO10](OH)2}·nH2O

The type of composition is similar to that of illite, except that the Y group is dominated by Fe3+, followed by Al and a small amount of Fe2+, Mg. The lack of positive charge caused by Al generation Si in the tetrahedral sheet is compensated by the interlayer cation K, and a small amount of K can be replaced by Na and Ca. K is less than 1 in the formula and is about 0.6-1.0 with interlayer water.

Identification characteristics

The crystal has a small, fake hexagonal shape, but it is extremely rare. It is usually a few millimeters in diameter of granular particles, distributed in loose siliceous or clayey carbonate rocks. Dark green to greenish black, and yellowish green, grayish green; opaque; usually dull; brittle;

Cause of occurrence

Under the shallow sea environment of the reduced state and the slow sedimentation, the formation of chert can be achieved. Temperate seabed with a depth of 10 to 250 meters (seawater temperatures of 15 to 30 degrees Celsius). Therefore, the glauconite is called Depth Indicator and it is also called Indicator of Slow Sedimentation. Most foramen within modern sediments in the shallow sea area of ​​the South China Sea have foraminifera, and some of them are accounted for by sea-greenstones, but they still maintain their original forms. This indicates that the formation of the marine greenstone is related to the biochemical effects of marine life. The chlorolite particles have an average diameter of half a millimetre. The glauconite is generally green to greenish black, pale greenish yellow to green on the flakes, and yellow-brown on oxidation. The chertstones are produced in quartz sandstone and in feldspar sandstone, limestone and dolomite. General green sand and green sand mud ash are important sea-green chlorite sediments and are also the main source of potassium.

Famous place of origin

Famous places of origin in the world include Birmingham, New Jersey, USA; and Liaoning, Hebei, Hubei, Yunnan and many other provinces.

Name Source: From the Greek "glaucos" means blue-green.

Crystal morphology: Rhombic columnar crystals; crystals have a small pseudo-hexagonal shape, but rarely seen; usually small round grains invade in impure limestone, clay rock, or siliceous rocks. Some are loose sand particles dispersed in coastal sand.

Crystalline and space group: monoclinic, C32h-C2/m;

Cell parameters: a0=0.525 nm, b0=0.909 nm, c0=1.003 nm, z=2;

Powder crystal data: 10.1 (1) 2.59 (1) 4.53 (0.8) 1.511 (0.6) 2.396 (0.6) 3.33 (0.6) 3.63 (0.4)

Physical properties:

Hardness: 2-3

Specific gravity: 2.2-2.8g/cm3

Cleavage: Cleavage (001) is rare

Color: dark green to green black, yellow green, gray green

Streaks: light green

Transparency: Opaque

Gloss: Matte

Luminous: No fluorescence

Others: Light green, light green, yellowish green or olive color under transmitted light. Significant polychromism

Optical properties

Biaxial crystal (-), Np=1.59-1.612, Nm=1.609-1.643, Ng=1.61-1.644, Double reflectance=0.0200-0.0320, 2V(calculated)=20-24, 2V(measured)=0-20 Dispersion r > v.

Uses: Potash fertilizer; pure can be used as pigments; due to cation exchange performance, can be used as hard water softener.