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Lignum vitae is hard and durable, and is also the densest wood traded (average dried density: ~79 lb/ft 3 or ~1,260 kg/m 3); [4] it will easily sink in water. On the Janka scale of hardness, which measures hardness of woods, lignum vitae ranks highest of the trade woods, with a Janka hardness of 4,390 lbf (compared with Olneya at 3,260 lbf, [5] African blackwood at 2,940 lbf, hickory at 1,820 ...
When testing wood in lumber form, the Janka test is always carried out on wood from the tree trunk (known as the heartwood), and the standard sample (according to ASTM D143) is at 12% moisture content and clear of knots. [3] The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the ...
Cross-section of an unprocessed piece of ebony wood. Ebony is a dense black/brown hardwood, coming from several species in the genus Diospyros, which also includes the persimmon tree. A few Diospyros species, such as macassar and mun ebony, are dense enough to sink in water. Ebony is finely textured and has a mirror finish when polished, making ...
Print/export Download as PDF; Printable version; In other projects ... Hardness scales may also refer to: Methods of measuring the deposit formation by hard water.
A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific comparison table for steels.
The sap wood of Diospyros ebenum is light-yellowish gray, with a glossy-black core occasionally containing light fibers. The wood also has metallic gloss with fine, smooth texture whose grains can be straight, a bit chaotically organized and wavy. Sawn block of Diospyros ebenum. In Sri Lanka, it is illegal to harvest and sell ebony wood.
Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale The Mohs scale ( / m oʊ z / MOHZ ) of mineral hardness is a qualitative ordinal scale , from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material.