Search results
Results from the WOW.Com Content Network
Corundum is a crystalline form of aluminium oxide (Al 2 O 3) typically containing traces of iron, titanium, vanadium, and chromium. [ 3 ] [ 4 ] It is a rock -forming mineral . It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. [ 7 ]
The Mohs Hardness Scale is the main scale to measure mineral hardness. Finger nail is 2.5, copper coin is 3.5, glass is 5.5 and steel is 6.5. Hardness scale is Talc is 1, Gypsum is 2, Calcite is 3, Fluorite is 4, Apatite is 5, Orthoclase Feldspar is 6, Quartz is 7, Topaz is 8, Corundum is 9 and Diamond is 10. Odor; Not always recommended.
Corundum from Brazil, size about 2×3 cm. The most common form of crystalline aluminium oxide is known as corundum, which is the thermodynamically stable form. [16] The oxygen ions form a nearly hexagonal close-packed structure with the aluminium ions filling two-thirds of the octahedral interstices. Each Al 3+ center is octahedral.
Corundum is the name for a structure prototype in inorganic solids, derived from the namesake polymorph of aluminum oxide (α-Al 2 O 3). [1] Other compounds, especially among the inorganic solids, exist in corundum structure, either in ambient or other conditions.
Sapphire (gem corundum of any color except red, especially blue varieties) Sard (a variety of chalcedony/quartz) Satinspar (a variety of gypsum) Selenite (a variety of gypsum) Simetite (a variety of amber) Smoky quartz (a brown or black variety of quartz) Soda niter (synonym of nitratine) Spectrolite (a variety of labradorite) Spessartite ...
Rosacea. What it looks like: Rosacea causes redness and thick skin on the face, usually clustered in the center.Easy flushing, a stinging sensation, and small, pus-filled pimples are other common ...
Dr. Giangreco says ticks can prompt local reactions following a bite. The classic rash of Lyme's is called Erythema migrans. "It can be circular or oval shaped and have crusting," Dr. Giangreco says.
The Munroe Falls Historical Society helped identify this photo from the early 20th century. This view is looking north on North Main Street (Route 91) near Munroe Falls Avenue.