Дата публикации: 2018-05-27 13:26
Cleavage is the tendency of a mineral to break along certain planes to make smooth surfaces. Minerals with different crystal structures will cleave in different ways, as Figure shows (below). Halite tends to form cubes with smooth surfaces, mica tends to form sheets, and fluorite can form octahedra.
Transaction Processing System are operational-level systems at the bottom of the pyramid. They are usually operated directly by shop floor workers or front line staff, which provide the key data required to support the management of operations. This data is usually obtained through the automated or semi-automated tracking of low-level activities and basic transactions.
Regional metamorphic rocks are formed in both heat and pressure, and have crystals that are aligned. The greater the pressure and temperature these rocks are exposed to, the larger the grains. Medium to high grade metamorphic rock formation occurs at a minimum temperature of 985 degrees F and a maximum temperature of 6,977 degrees F, but also at much lower temperatures. Some examples of metamorphic rocks are Slate, Marble, and Granulite.
6695s, "regard as the same," from French identifier , from identité (see identity ). Sense of "recognize" first recorded 6769. Meaning "make one (with), associate (oneself)" is from 6785. Sense of "serve as means of identification" is attested by 6886. Related: Identified identifying.
Hardness is a mineral''s ability to resist being scratched. Minerals that are not easily scratched are hard. You test the hardness of a mineral by scratching its surface with a mineral of a known hardness. Mineralogists use Mohs Scale, shown in Table (above), as a reference for mineral hardness. The scale lists common minerals in order of their relative hardness. You can use the minerals in the scale to test the hardness of an unknown mineral.
Eric, hope you can help me with this one. Purchased it two years ago, and I believe it is Mahogany. Can you tell by the picture?
Hi everyone, hi Eric
any idea about this ? I have to figure out in order to put the right painting or whatever on it.
Hi Deborah, I 8767 m not a specilist but am a professional painter and finish quite a few different kinds of wood To me the grain and color resemble either 8776 Cypress or Douglass fur 8776 Being said they both have a very distinct smell when cut.. I hope this helps????
HDPE feels harder and essentially, more crinkly. Many plastic shopping bags are manufactured from HDPE and the easiest way to distinguish them from LDPE bags, is from the sound the make when you crinkle them in your hands. If the sound is soft and swishing (think of green leaves blowing in the trees), then you have identified LDPE if the sound is crisper and crinkly (think of dry leaves being squished together), then you have HDPE. The two sounds are quite distinct.
Fluorescence: While certain woods can appear basically identical to one another under normal lighting conditions, when exposed to certain wavelengths—such as those found in blacklights—the wood will absorb and emit light in a different (visible) wavelength. This phenomenon is known as fluorescence , and certain woods can be distinguished by the presence or absence of their fluorescent qualities. See the article Fluorescence: A Secret Weapon in Wood Identification for more information.