中文摘要：

贝壳是一种常见的首饰的材料,其种类繁多,经常被加工或处理成各种形状的饰物,难以判断其原 始种类 .本次对一串疑似 “ 贝壳”的杂色手排样品进行未知鉴定,并将它与市场上常见的贝壳首饰进行对比研 究 , 了解市场上贝壳首饰的主要品类及基本特征 .利用折射仪、静水称重法等方法对手排及其它贝壳饰品进 行基本宝石学特征测试,采用 X 射线荧光光谱仪、 X 射线粉末衍射仪、傅里叶变换红外光谱仪、拉曼光谱仪对 其成分及谱学特征进行测试,最后利用扫描电子显微镜对内部结构进行观察 .经过测试和分析,得出手排成 分为方解石,呈细长板片状排布,整体呈近似放射状分布,密度偏低,表面呈丝絹光泽,推测其取材于方解石型 贝壳或贝壳方解石层 .市场上的贝壳首饰主要矿物组成为文石,晶体呈砖墙状密集平行排布,它们的相对密 度多高于手排样品 , 且表面显示珍珠光泽和晕彩 .此外手排没有出现有机染料染色的特征,推测其颜色是由 类胡萝卜素所致 .

英文摘要：

Shell is a kind of gem materials. There are many kinds of sh e l ls, which are usuallycut and treated to different ornaments. Therefore it is difficult to identify their original shapes. Recently, a special kind of brccelet was found in the market. It is made of fourteen rectangular be ad s, which have four kinds of colour： P u rp le , orange, pink paque and has a laminated s tru c tu re. The pink and orange part of bracelet and the bracelet has many things in common with shells. Therefore the study made compar-- son of the bracelet and other shell jewelr ies, which included Monetarmargaritifera , Pin c d a tama x ima , Trochus maculatus Linnaeus , Pteria penguin , etc. The fundamental gemmological characteristics of the bracelet and the other shell jewelries were tested by refractometer, balance, e tc , and the composition and spectral features were meas-ured by X-ray fluorescence spectrometer （XRF） , X-ray diffraction （XRD） , Fourier trans for-mation infrared spectrometer （FT IR ） and Raman spectrometer. The structure of the samples were analyzed by scanning electron microscope （SEM）. According to the te s t r e su l ts , the re-fractive index of the samples are all between 1. 530 and 1. 685 # and the average refractive in-dex of the sample is 1. 57. The average relative density of the sample is 2. 57, which is a li--tle lower than the other shell jewelries. It may be caused by the difference of composition andstructure , or by the influence of the hole on i t. They have similar are all rich inCa and Sr. They have completely different mineral composition and s tru c tu re. The bracelet is mainly made of calcite and it has a lath-like s tru c tu re. The calcite crystal was arranged radically and has a low relative density and silky lu s te r. The shell jewelries in themarket are mainly made of aragonite and have a brick-wall s t ru c tu re , which is almost fromnacre. The aragonite crystal was in para