火焰梦幻——海螺珍珠

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粉色吸引
尽管大凤螺的螺壳被前加勒比文化中用作意识乐器，但是知道1800年以前都没有将海螺珍珠作为珠宝使用的记载。剩下的另外一篇有，略。
天然之美
                
                海螺珍珠是独特而昂贵的有机宝石。从技术上讲，它应该称作“nacreous encrusted foreign bodies”(翻译无能，╮(￣▽￣")╭ )。但是实际上它是海螺包裹钻入体内的还蠕虫时形成的钙质结晶【calcareous concretions】。同前文，略。不同于珍珠质形成的珍珠——在1920年左右已经能够人工养殖——海螺珍珠的养殖技术刚刚出现，Florida Atlantic University's Harbor Branch Oceanographic Institute (HBOI)【见引用】声称，他们的研究队伍已经能够养殖有核珍珠【nucleated pearl】与无核珍珠【non-nucleated pearl】。相信很快就会看到跟多研究内容。
特殊的珍珠
不论是颜色，形状还是独有的火焰纹，海螺珍珠都是独一无二的有机宝石。 颜色从洋红色，三文鱼的粉橙色，金色到粉色，甚至是白色。多数的海螺珍珠都是椭圆形，正圆的难得一见。最为独特的是它的火焰纹，令人迷恋的火焰纹甚至不会出现在每一粒达到宝石级的珍珠上。最理想的海螺珍珠是粉红色，椭圆形，带有变彩与火焰纹。
珠光VS变彩
对于珍珠质形成的珍珠，闪亮的珠光是重要的特征，而伴彩对于海螺珍珠则更为重要。珍珠的变彩以非常独特的方式出现：牡蛎和贻贝有闪亮的伴彩（表面上有彩虹一般的颜色），海螺珍珠的变彩则是云状的火焰纹理，又是看起来就如同人类虹膜的结构。二者的不同外观是由其结构带来的。珠光是因为书曾半透明霰石对光的反射和霰石光滑边缘的衍射造成。变彩并不独属海螺珍珠，许多矿石都有变彩效应，例如虎眼石，猫眼金绿柱石。但是，在所有珍珠之中，只有海螺珍珠拥有变彩效应。这种变彩来自向心的纤维状结晶。火焰装的纹理来自珍珠表面垂直结晶的光学效应。
其他宝石学性质
                
                大小：通常直径2-3mm，大约0.2-0.3克拉。
折射率：与颜色有相当大的关系。平均值是1.51。
比重：依旧与颜色有关。棕色比重较低，2.18-2.77；白色和金色为2.82-2.86；粉色不含空隙，比重为2.84-2.87。
硬度：粉红色最硬为5-6，棕色为4-5。
韧性：根据报告，海螺珍珠的韧性高于牡蛎珍珠。
化学成分：CaCO3
UV测试
有传言表示海螺珍珠的颜色会因阳光褪色。于是我们对海螺珍珠进行了UV测试。经过4个月的间歇曝光，并未发现又任何程度的颜色改变。也许哥伦比亚海岸以外产出的珍珠有褪色现象。食物的成分，海螺的具体种类，海洋环境都可能对珍珠造成影响。文/Tannin
巨型凤凰螺，大凤螺
 
                
                
大凤螺是一种大型的植食软体动物，背着巨大的螺旋状螺壳生活在加勒比海峡，福罗里达群岛，百慕大与南美靠近北部的温暖暖浅海。
The Queen Conch (Strombus gigas Linnaeus, 1758), is a large herbivore mollusk with a spiraled shell that dwells in the shallow warm waters of the Caribbean region, the Florida Keys, Bermuda and Central and the northern part of South America. The larvae of the Queen conch are pelagic -which means they are free swimmers- and spend their first month or so in the water column. After that, they settle on the seafloor in shallow warm waters where they begin their metamorphosis; early juveniles are seldom seen, since they spent most of daytime buried in the coarse sand. As they grow older and larger, they spend less time buried and by the time they are approximately one year old, they give up burying, except during the winter months.Queen Conch reach their sexual maturity at around three and a half years old. They have separate sexes and a female may spawn 9 times in a single reproductive season, from May to November. Each egg mass may contain between 350,000 and 500,000 eggs. However, only a small percentage of the larvae survive, and the juveniles up to one year old are easy prey to octopuses, fishes and marine turtles.Queen Conch have a large strong foot and heap rather than crawl on the seafloor, and they can do it amazingly fast for a snail with a large heavy shell. Their populations are migratory; they move in large groups, inshore during the spring and offshore during the fall. In addition, as they become older, their migratory grounds increase in size: an adult Queen Conch may have a home range of nearly 8 kilometers per season.
QUEEN CONCH FISHERY
 
                
                For the most part, Queen Conch fishery is artisanal or small scale. It involves relatively small boats powered by outboard engines or sail oars, and carrying one to four divers and a driver. The divers may not only harvest Conch, but also other shallow water species like lobsters, depending on the season. Their method usually consists of free diving up to 12 meters deep, and the use of hooked poles. With the decline of shallow water populations, modern gear, such as scuba diving and compressor diving (hookah) that allow the divers to reach depths up to 30 meters or more, have become the dominant gear used to harvest Queen Conch. Since they can stay underwater for longer periods, divers provided with this gear usually discard the shells underwater, taking on board larger amounts of meat.Industrial Queen Conch fishery has developed in some countries like Jamaica, Honduras and Dominican Republic. This industry uses large vessels that can reach offshore banks, each cone carrying 40 or more divers and fishing trips may take as long as a full week. The actual fishing is done with smaller boats like those used in the artisanal sector; fishing gear usually includes scuba or hookah. The larger boats serve as 'mother vessels' where the divers stay overnight, using it as a base for their daily fishing trips. Sometimes these large boats are also used as 'packer boats' where the daily catch is collected and taken to the processing plants.
CONSERVATION ISSUES
                
                The over-exploitation of the resource due to the use of modern fishing gear and industrial fishery, has led to the decrease of the populations of Queen Conch in areas where it used to be abundant. Therefore, in 1992 the Strombus gigas has been included in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). Today, 175 countries have joined CITES. This involves very strict control from government authorities at every stage from fishing to exportation of Strombus gigas products. In addition, any further re-export of pearls requires a CITES export license. Some countries have already begun restoration efforts that include translocation of adult conchs, marine protected areas, regulations, closures, and aquaculture for the recovery of stock, as well as ranching for commercial use. CITES authorities have imposed a ban on international trade of Strombus gigas products originating from several countries of the region including Haiti and The Dominican Republic due to their poor results.
ALL OUR QUEEN CONCH PEARLS ARE CITES CERTIFIED EXPORTS!
QUEEN CONCH AQUACULTURE AND RANCHING
                
                 The history of aquaculture of the Queen Conch is by no means recent: it has been taking place since the 1970's in order to replenish over-exploited habitats and to produce meat for the market, but it was only in 1984 that the first commercial conch was farm established in the Turks and Caicos Islands.Large-scale conch culturing techniques are now well established. It all begins with the collection of the egg masses in the summer breeding season, with the purpose of relocating them in an underwater egg farm. Four days later, the veligers hatch from the egg masses, and after three weeks of larval stage, they begin their metamorphosis. This process is enhanced by means of a red seaweed extract, and by the time the juveniles are one year old, they have grown a seven-centimeter shell.The conch farm in Turks and Caicos has developed ranching in large sea pens where seven-centimeter conchs are placed until they reach the market size of 15 centimeters. These mesh pens, with a diameter of 70 feet, are placed in shallow water and can hold up to 5,000 conch each. This high density requires the conch in the pen to be supplemented with formulated feeds several times a week.The average cost of culturing an individual conch until it reaches 15 centimeters has been calculated in US$ 9.00. Given such high costs, experts recommend that reproductive stock replenishment based on aquaculture be used only in marine protected areas where collection is banned.
THE COLOMBIAN CASE
Despite its diminishing CITES fishing quota, Colombia still ranks in the top 10 countries in total global exports of Queen Conch products. Colombian production comes mainly from the San Andres, Providence and Santa Catalina archipelago and it is a primary source of livelihood for many families, as well as an important species for local tradition. Therefore, strict regulations have been put into practice in order to protect stock and recover populations. These regulations include the attribution of a quota to each fishing company, the prohibition of the use of hookah and scuba, a minimum size of the shell of 19 centimeters and a closure from June to November. As a result of the total closure of the fishery of the Strombus gigas in the archipelago from June 2004 through November 2006, a significant increase in the natural population is expected.
 At present, the research team of Coralina Foundation is looking for alternative ways to allow traditional fishers a better quality of life while engaging them in the active protection and recovery of the Queen Conch populations. The project integrates environmental conservation education, aquaculture, and the restocking of marine protected areas with reproductive stock. The aquaculture techniques used in the archipelago are very similar to those used in the conch farm in Turks and Caicos. The recently declared Seaflower Marine Protected Area, with no-take-zones, provides a perfect setting for the recuperation of the species in areas where natural recovery has not yet taken place.
 
                
                
原文：http://www.caracolgems.com/about_pearls.html
引用：
 CITES (2003): AC 19 Doc. 8.3 (Rev. 1). Review of significant trade in specimens of Strombus gigas, available at:
http://www.cites.org/eng/com/AC/19/E19-08-3.pdf
 Federman D. (2007): The pink pearl: A natural treasure of the Caribbean: SKIRA Editore, Milano.
 Fritsch E., Misiorowski E. (1987): The History and Gemology of Queen Conch "Pearls", Gems & Gemology Volume 23, Issue 4, p.208-p.221.
 Theile S. (2001): Queen conch fisheries and their management in the Caribbean. Traffic Europe, available at:
http://www.traffic.org/content/329.pdf
 Scientists are first to 'unlock' the mystery of creating cultured pearls from the queen conch. Public release date: 4-Nov-2009 available at:
 http://www.eurekalert.org/pub_releases/2009-11/fau-saf110309.php