I drop my TB in this earthcache that every cacher can discovered it.
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汉白玉特指北京房山出产的白色大理石，质地坚硬洁白。主要成分是碳酸钙，化学式是CaCO3，其他成分还有MgCO3和SiO2等。
颜色洁白的细粒大理岩，质地坚硬，是上等的建筑和雕刻材料。基本上它并不溶于水。它可存在于以下形态：霰石、方解石、白垩、石灰岩等。
岩石：汉白玉
岩石类型：大理石（变质岩）
粒度： 0.5至2毫米
质地：固体
成分：碳酸钙
颜色：乳白色，浅灰色，淡黄
形态：霰石，方解石
1）纯质碳酸盐大理岩，主要是方解石、白云石。
2）硅质碳酸盐大理岩，主要是滑石、石英、透辉石、粒硅钙石等。
3）泥质碳酸盐大理岩，主要是蛇纹石、绿泥石、方柱石、正长石等。
在故宫里每一个宫殿的前后两面，都有石制的台阶，在台阶的正中是一个斜制的长条石，上面雕刻着龙、凤、海水江崖等各种图案，这个东西叫做“灵墀”。故宫里最大的灵墀，在保和殿的后面，被称为“云龙石雕”。
这是紫禁城中最大的一块石雕，汉白玉石质，长16.57米，宽3.07米，厚1.70米，重为250吨以上。最早是明朝雕刻，清朝乾隆时期又重新雕刻。石雕四周刻有缠枝莲花纹，下部为海水江牙，中间雕刻着流云衬托着九条蟠龙和州龙，形像生动，雕刻精细，一丝不苟，生机盎然。一般认为云龙石雕上的雕刻是皇权的象征，代表皇帝的权利至高无上，无可撼动。
云龙石雕的石料产自京西房山大石窝，距离紫禁城大约有60公里。当时拖运这样重的巨石需要民夫万人以上，采取每隔0.5公里便凿开一口水井，利用寒冷的冬季，在地面洒水成冰，利用冰的来减少摩擦力，再将巨石一点一点拉到紫禁城。
任务：
为了登记这个地理宝藏，你必须进入故宫参观，门票40或60元，因季节而异。你可以先log，然后将以下问题的答案发到我的邮箱里，以确保您的log是真实有效的。如果在两个星期内没有收到你的邮件，我将会删除您的log。
1）确定云龙石雕是什么类型的汉白玉（纯质、硅质、泥质大理石）。
2）以你的观察，这块汉白玉颗粒是否细致（0.5、1、2mm）？
3）与云龙石雕合个影（这个不是必须的）。
请不要将问题答案写在您的log里。
Alabaster is a kind of marble. By Fangshan of Beijing, the Alabaster have so hard white. The main ingredient is calcium carbonate, the chemical formula is CaCO3, the other components are MgCO3 and SiO2, etc.
The fine Alabaster with hard that is an excellent building and engraving material. Basically it does not dissolve in water. It can be found in the following forms: aragonite, calcite, chalk, limestone, etc..
Rock: alabaster
Rock type: marble (metamorphic rock)
Granularity: 0.5 to 2 mm
Texture: solid
Ingredients: calcium carbonate
Color: milk white, light gray, pale yellow
Form: aragonite, calcite
1)pure carbonate marble: mainly calcite and dolomite.
2)siliceous carbonate marble: mainly talcum, quartz, diopside, granular silicalite and etc.
3)argillaceous carbonate marble,: mainly serpentine, chlorite, orthopite and etc.
In the Forbidden City every palace before and after the two sides, there are stone steps, the step is in the middle of a long stone oblique, carved with dragon and Phoenix, sea cliff Jiang and other designs, this thing called “Ling Xi". The spirit of Ling Xi in the Baohe Palace, in the back of the hall of preserving harmony, known as " Clouds-Dragon Stone Carving ".
This is largest alabaster stone in the Forbidden City, 16.57 meters long, 3.07 meters wide, 1.70 meters thick, weighs more than 250 tons. It was first carved in the Ming Dynasty and again in the Qing Dynasty during the Qianlong emperor. Around the stone engraved with lotus pattern, the lower sea river carved teeth, middle clouds against the nine dragons and dragon state, vivid image, fine carving, strict in demands of vitality. It is generally believed that the sculpture on the stone carving of Clouds-Dragon is the symbol of the imperial power, and the right to represent the emperor is supreme and unshaken.
The alabaster stone material is produced from the Big-stone-nest in Fangshan, southwest of Beijing. It is about 60 kilometers from the Forbidden City. When such a heavy haul boulders need to turn more than ten thousand people, take every 0.5 km digging a well, the cold winter, ice on the ground water, use ice to reduce friction, then the rock point to the forbidden city.
Task:
In order to log this Earth Cache you must visit The Forbidden City in Beijing China（ticket：40or60RMB）。You can immediately log and then send the answers of the following questions to my email or message to make sure your log is valid. If I did not receive the mail or message within two weeks, I will delete your log。
1) Determine alabaster type of Clouds-Dragon Stone Carving (pure, siliceous and argillaceous marble).
2) For your observation, what meticulous is the alabaster grain (0.5, 1, 2mm)?
3) Make a photo with Clouds-Dragon Stone Carving. (optional).
Please do not write the answers in your log.