Pyrolusite (Pyolusite)
[Chemical composition] Fine particles and cryptocrystalline blocks often contain mechanical inclusions such as Fe 2 O 3 and SiO 2 and contain H 2 O. [Crystal structure] tetragonal system; [Form] Complete crystals are rare, sometimes in the form of needle-like or radial aggregates (Fig. Y-15). Often in the form of kidneys, tuberculosis, massive or powdery aggregates. FIG Y-15 of needle assembly soft manganese ore [Physical properties] Black, the surface often has a light blue ochre; streaks black; semi-metallic luster to earthy luster. Cleavage parallel {110} is complete. The hardness varies depending on the thickness of the crystal, and the crystallinity can reach 6 and the cryptocrystalline block drops to 2. The relative density of the crystals is 4.7 to 5, and the bulk is reduced to 4.5. Crisp. [genesis and production] are mainly formed in weathering and sedimentation. It is one of the main manganese minerals in the sedimentary genesis manganese deposit. A large number of pyrolusite deposits are found in sedimentary manganese deposits in Hunan, Guangxi, Liaoning, and Sichuan. The formation of large black pollution is called manganese cap. [Identification features] With its black color, black streaks, and brittleness, crystallized ones have complete cylindrical cleavage, which is characterized by low hardness and easy dirt. In addition, the dropped H 2 O 2 was vigorously foamed. [Main use] is the main ore mineral of manganese.
Why is the air dry in winter?
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a 0 =0.439 nm, c 0 =0.286 nm; Z=2. Rutile crystal structure belongs. 
What we call humidity is divided into two kinds, absolute humidity and relative humidity.
Absolute humidity refers to the amount of water molecules per cubic meter of air.
Relative humidity refers to the ratio between "absolute humidity" and "saturation humidity".
"Saturation humidity" refers to the absolute humidity required for the water vapor in the atmosphere to reach saturation at a certain temperature. Saturation humidity is also closely related to temperature. The higher the temperature, the greater its value.
The drying or wetting we usually feel does not have a great relationship with absolute humidity, but mainly depends on relative humidity. Therefore, this issue should be discussed as follows:
On the one hand, when the temperature is low in winter and the saturated vapor pressure is small, the absolute humidity of the air is small.
On the other hand, when the temperature is low in winter, the value of saturated humidity is also small. When the absolute humidity is the same, the relative humidity is greater.
Generally speaking, there are positive and negative effects of temperature on humidity. Which role plays a major role should be discussed according to the actual situation.
In some areas it gets dry in winter, while in others it may get wet. The temperature is low in winter. Even if the relative humidity is 100%, the water vapor content is still very low. After we inhale air, the air is heated to body temperature, and the relative humidity will become very low, so we will feel dry. The air we exhale is basically saturated steam at body temperature, so we consume a lot of water when we breathe.
The air near the skin will also be heated, so the moisture of the skin is also easy to evaporate
The doctor suggested that an Aroma Diffuser should be placed indoors, which can effectively and immediately solve the problem of indoor air drying, humidify the air and solve the problem of air drying. The ultrasonic aroma diffuser should be used, and the fog should be sprayed out through vibration