無機(jī)非金屬材料專業(yè)英語-寶石的力學(xué)性能

1、Unit 27 Mechanical Properties of Gemstones寶石的力學(xué)性能n1、Gemstones may show mechanical characteristics as a result of the application of force, for example gemstones may be damaged, broken and, in some cases, be divided into two or more pieces, etc. n由于施加的力所致，寶石可能會表現(xiàn)出力學(xué)特征，如在一些情況下寶石可能被損害、破碎、被分成兩片或者多片等。 nM

2、echanical properties involved in gemology are cleavage, parting and fracture, hardness, density.n寶石涉及到力學(xué)性能有斷裂、分離和破碎、硬度、密度。Cleavage, Parting and Fracture 斷裂、分離和破碎斷裂、分離和破碎 n2、Cleavage is the ability, possessed by some gemstones, to split along certain well-defined directions leaving more or less flat

3、faces (possibly showing pearly luster), lying parallel to crystal faces, even though crystal faces may not be present in particular specimen.n斷裂是一些寶石具備的一種能力，可以沿著清晰的紋路分裂，留下的幾乎是平面（可能顯示出珍珠光澤），并與晶面平行，即使在一些特殊的樣品中晶面了可能不會存在。n3、In certain minerals, this difference in strength is sufficient to allow the crys

4、tal to split, parallel to the densely packed planes, when appropriate force is applied. n在一些材料中，當(dāng)施加一定的力時，這些強(qiáng)度的差異足可以使晶體分裂，并平行于密排面。 nThis particular type of splitting is called cleavage, is always parallel to an ideal crystal face, and can only occur in a single crystal.n這種特別的分裂類型成為斷裂，總是平行于理想晶體面，并且只在單

5、晶體中發(fā)生。n4、Because cleavage is a directional characteristic of weak atomic bonding, any direction in a crystal lying parallel to layers of atoms is a potential cleavage direction, although most minerals resist splitting along these various planes.n由于斷裂是微弱原子結(jié)合的方向性特征，晶體中任何平行于原子層的方向都是潛在的斷裂面，雖然大多數(shù)礦物質(zhì)在這些不同

6、位面的分裂會受到限制。 nIt is for this reason that cleavage is a highly diagnostic feature, possessed to a marked degree by only a few gemstones.n正因?yàn)槿绱?，斷裂是非常特有的特征，僅僅在為數(shù)不多的寶石中才會有。n5、When we refer to a gemstone with noticeable cleavage, we need to discuss not only its direction, but also the cleavage quality.n當(dāng)我

7、們提到一個有明顯解理面的寶石時，我們不僅需要討論它的方向，還要討論解理面的質(zhì)量。 nCiting the examples already given, diamond has perfect octahedral cleavage, and graphite has perfect cleavage parallel to the basal plane (of the hexagonal crystal), called basal cleavage. n引用已有的例子，金剛石具有完美的八面體解理面，石墨具有完美的與基面平行的解理面（是六面體晶體），稱為基解理。 nOther possib

8、le directions of cleavage include rhombohedral, prismatic, pinacoidal. n其他可能的解理面方向包括：斜方六面體、菱形、地面的。 nCleavage faces may often be recognized by a series of very shallow steps, where the break has occurred along several layers of atoms at the same time.n解理面經(jīng)?？赡芙?jīng)過一系列非常膚淺的程序進(jìn)行驗(yàn)證，在解理面上同時會沿著原子的幾層會發(fā)生破裂。n6、T

9、he gemmologist obtains benefit from cleavage because it is an aid to identification, and the cutter obtains some benefit because poor quality areas can be removed easily from rough materials. n寶石學(xué)家獲益于解理面，因?yàn)樗梢杂兄阼b定，同時切削也獲得了一些益處，因?yàn)橘|(zhì)量差的方面可以輕易的從原材料中去除。 nWhile this feature is of particular importance to

10、 the diamond cutter, there are probably more disadvantages than advantages associated with cleavage. n雖然對金剛石切削來說這種特征尤為重要，但是解理面的缺陷可能遠(yuǎn)大于優(yōu)勢。 nIt is virtually impossible to polish a gemstone parallel to a cleavage direction.n實(shí)際上不可能將寶石拋光至于解理方向平行。n7、Parting is the breaking or splitting along lamellar twin

11、ning planes. n裂理是沿著薄的孿生面的破壞或裂開。 nSometimes the internal structure of a gemstone causes a physical effect similar in appearance to cleavage.n有時寶石的內(nèi)部結(jié)構(gòu)會引起表面上看起來和解理相似的物理效應(yīng)。 nHowever, the gemstone breaks or splits along twinning planes. n但是，寶石是沿著孿生面破碎或裂開的。nFor example ruby exists splits at rhombohedral

12、and basal directions.n例如，紅寶石在斜方六面體和底部方向存在裂紋。n8、Fracture is the random, non-directional breakage, which occurs in most gemstones as a result of sharp impact, and is often considered to be a typical and identifying feature of glass. n破碎是任意的、無方向性的破壞，存在于大多數(shù)寶石，由于突然的作用力所致，經(jīng)常作為玻璃的典型和標(biāo)志性特征。 nUp to a point t

13、his is true, but it is also quite typical of amorphous substances in general, and of those crystalline materials that have no pronounced planes of weakness, for example, quartz or beryl.n在一點(diǎn)上這是正確的，但是它也是一般非結(jié)晶物質(zhì)的典型特征，也是沒有明顯薄弱面的晶體材料的典型特征，如石英和綠寶石。 n9、Several types of fracture are recognized, those norma

14、lly seen by the gemologist being conchoidal or shell-like. n破碎的幾種類型已經(jīng)是公認(rèn)的，也就是那些通常被寶石學(xué)家看作貝克狀的或類似貝克的。 nWhen a mineral breaks with curved concavities, then the break is called conchoidal fracture, from the resemblance of the concavity to the valve of a shell.n當(dāng)一種礦物質(zhì)破裂成弧形凹面，那么這種破裂稱為貝克狀破裂，因?yàn)槠屏寻济嫦嗨朴跉け妗10

15、、The fibrous, tough structure of nephrite jade produces another kind of fracture - hackly. n纖維狀、堅硬的軟綠玉結(jié)構(gòu)產(chǎn)生另外一種類型的破碎-鋸齒狀的。nThis refers to the uneven, and often jagged, break that occurs when this material is broken.n當(dāng)這種材料破裂后，就會產(chǎn)生不規(guī)則的，并且經(jīng)常是邊緣粗糙的裂紋。n11、Other terms are used as earthy, splintery signific

16、ance for the in mineralogy to describe fractures such and uneven, but these has little significance for the gemologist.n其它的條件也被應(yīng)用于描述這樣的裂紋和不規(guī)則，如礦物學(xué)的泥土的、破裂意義，但是這些對寶石學(xué)家意義不大。Hardness 硬度硬度n12、Hardness is the ability of gem to withstand abrasion, and is one of the prime qualities of a gem material. n硬度是寶石

17、的耐磨能力，是寶石材料的主要質(zhì)量指標(biāo)之一。 nThe scale of hardness, which is used universally for gemology and mineralogy, is comparative one.n硬度等級是一個相對等級，廣泛的用于寶石學(xué)和礦物學(xué)。n13、The German mineralogist, Friedrich Mohs produced practical scheme for hardness assessment in 1822. n德國的礦物學(xué)家Friedrich Mohs 在1822年制定了硬度評價的實(shí)用方案。 n After

18、a number of selection trails, he brought together ten easily obtained minerals, which could be obtained in a high degree purity, and listed them in order of ability to withstand scratching by other members of the group. n經(jīng)過大量篩選，他把十種容易獲得的礦物質(zhì)放在一起，這些礦物質(zhì)可以在高純度下獲得。團(tuán)隊的其他成員將這些礦物質(zhì)依據(jù)他們的耐磨能力大小的順序排列。 nThis res

19、ulted in which is now known as Mohs Scale of Hardness. n以下就是這個實(shí)驗(yàn)的結(jié)果，也就是現(xiàn)在所為人知的莫氏硬度指標(biāo)。nThe scale in increasing order of resistance to abrasion is:nTalc 1 gypsum 2 calcite 3 fluorite 4 appetite 5 orthoclase 6 quartz 7 topaz 8 corundum 9 diamond 10n14、 It is important to note that this is only an order

20、 of hardness and that the difference in hardness between any two adjacent members of the scale is not an indication that a uniform difference of hardness exists between other pairs of members. n重要的是應(yīng)該注意這不僅僅是硬度的順序排列，并且指標(biāo)中兩相鄰成員之間的硬度差異并不表示：其它成員對之間存在一個統(tǒng)一的差異。 nBut the comparable hardness of some other co

21、mmon substances would be noted, for example finger nail (2.5), window glass (5-5.5), steel knife blade (5.5-6) and steel file (6.5-7).n但是某些其它常見物質(zhì)的相對硬度應(yīng)該引起注意，例如：指甲2.5，窗玻璃5-5.5，鋼制刀片5.5-6，鋼銼6.5-7Density and Specific Gravity 密度和比重密度和比重n15、The carbon atoms that unite to form either graphite or diamond, d

22、o so in different ways, not only producing difference in hardness and cleavage, as described in the earlier section, but also differences in their weight/volume ratios, which are termed as density.n碳原子以不同的方式形成石墨或者金剛石，不僅僅造成如前所述的了兩者的硬度和解理的差異，也造成了體積/重量比率的不同，也就是密度。n16、The density of every substance, including all gemstones, is determined by the arrangement of its constituent atoms. n每一種物質(zhì)的密度，包括所有的寶石，是由組成原子的排列決定的。nDensity is measured by the number of units of mass contained in 1 unit volume.n每一種物質(zhì)的密度，包括所有的寶石