地质现象的位置
在永定门北侧广场上屹立着一块巨石，这是世界上已知的最大的一块和阗玉原石。这块巨石产自昆仑山，为了庆祝北京奥运会成功举办，于2009年放置于此。2008年北京奥运会奖牌首次采用玉石材质，这种玉石便是和阗玉。
和阗玉
和阗玉，又称和田玉，古名昆仑玉，原产西域莎车国、于阗国（今中国新疆维吾尔自治区和田地区），已有一千多年历史。《千字文》当中的“玉出昆冈”的“玉”指的就是和阗玉，“昆冈”指的是昆仑山。考古结果证明，和阗玉传入中国，为时更早，距今七千年前的仰韶文化遗址发现有和阗玉。
和阗玉的化学式为Ca₂(Mg, Fe)₅Si₈O₂₂(OH)₂，其主要成分是角闪石族中的透闪石-阳起石系列。和田玉中，透闪石含量越高，品质越好。
和阗玉是一种珍稀玉种，莫氏硬度在6.5—6.9之间，质地细腻，韧性极高，不易碎，耐磨损。和阗玉独具温润柔和的油脂光泽，加上半透-微透的透明度，更突出其油脂光泽的柔润细腻，观赏价值极高。和阗玉的坚韧使它经得起精雕细琢，再精细的工艺造型也能雕琢得工整流畅、清晰完美。
和阗玉的矿物组成中含有钙、铁、锰、锌、铜等十三种微量元素。按产出地不同可分为山料、山流水和仔料。
您的任务
请通过消息中心或电子邮件将以下问题的答案发送给我。然后，您可以立即记录Earthcache。如果您在回答问题时遇到任何问题，请随时与我联系 - 我很乐意为您提供帮助。如果Log后七日内我没有收到您的消息或邮件，或您在Log中直接回答了问题，我将删除您的Log。
1️⃣ 请您估测一下这块巨石的长度与高度。
2️⃣ 这块巨石可以观察到透明或者半透明吗？其表面的风化痕迹明显吗？
3️⃣ 请您根据学习的内容，判断这块巨石属于软玉还是硬玉？
4️⃣ 请以这块巨石为背景，拍摄您自己、GPS 或属于您的其他物品的照片，并将其附加到您的日志中。
Location of the Geological Phenomenon
On the northern plaza of Yongdingmen stands a massive boulder, known as the largest Hetian jade raw stone in the world.
This giant jade boulder originates from the Kunlun Mountains and was placed here in 2009 to commemorate the successful hosting of the Beijing Olympic Games. In 2008, jade was used for the first time in Olympic medals, and the material chosen was Hetian jade.
Hetian Jade
Hetian jade, also known as Hotan jade and historically referred to as Kunlun jade, originated in the ancient Western Regions—specifically the Kingdoms of Shache and Yutian (in today's Hetian Prefecture, Xinjiang Uygur Autonomous Region, China). It has a history of more than a thousand years. In the Thousand Character Classic, the phrase 'jade comes from Kun Gang' refers to Hetian jade, with 'Kun Gang' denoting the Kunlun Mountains. Archaeological evidence indicates that Hetian jade was introduced into China much earlier: jade artifacts identified as Hetian jade have been discovered at Yangshao culture sites dating back approximately 7,000 years.
The chemical formula of Hetian jade is Ca₂(Mg, Fe)₅Si₈O₂₂(OH)₂. Its primary mineral components belong to the tremolite–actinolite series of the amphibole group. Generally, a higher tremolite content corresponds to finer quality.
Hetian jade is a rare variety of jade with a Mohs hardness of about 6.5–6.9. It is fine-grained, exceptionally tough, resistant to breakage, and durable against wear. It is renowned for its warm, gentle, oily luster; combined with its semi-translucent to micro-translucent appearance, this luster appears especially soft and refined, giving it high aesthetic value. Its toughness allows it to withstand intricate carving, enabling even the finest designs to be rendered smoothly, cleanly, and precisely.
The mineral composition of Hetian jade includes calcium, iron, manganese, zinc, copper, and a total of thirteen trace elements. Based on occurrence and transport, it can be classified into mountain material, mountain-stream material, and river pebble material.
Your Tasks
Please send your answers to the following questions via Message Center or email. After submitting your answers, you may immediately log the EarthCache. If I do not receive your answers or message within seven days after your log, or if you post the answers directly in your log, your log will be deleted.
1️⃣ Please estimate the length and height of this boulder based on your observation.
2️⃣ Can you observe any transparent or semi-translucent areas in the stone? Are there obvious signs of weathering on its surface?
3️⃣ Based on what you have learned, determine whether this boulder is nephrite (soft jade) or jadeite (hard jade).
4️⃣ Please take a photo with this boulder in the background that includes yourself, a GPS device, or another personal item, and attach it to your log.