玛瑙 Agate

化学式：SiO2

硬度：6.5至7度

比重：2.55至2.91

折光率：1.535至1.539

产地有：印度、巴西、美国、埃及、澳大利亚、墨西哥等国。墨西哥、美国




玛瑙的历史十分遥远，它是人类最早利用的宝石材料之一。主要产于火山岩裂隙及空洞中，也产于沉积岩层中，是二氧化硅的胶体凝聚物，与水晶，碧玉等一样，也是一种石英矿，其化学成份是二氧化硅。在矿物学中，它属于玉髓类，一般为半透明到不透明。

一般来说，玛瑙质量好坏的鉴别和经济价值的评定主要分级如下：

1、特级：纹带美丽；颜色纯正、明快的红、蓝、紫、粉红色；透明度好，即半透明；无裂纹、无砂心、无杂质；块重约5公斤以上者。
2、一级：纹带美丽；颜色纯正、明快的红、蓝、紫、粉红色；透明度好，即半透明；无裂纹、无砂心、无杂质；块重约2－5公斤者。
3、二级：纹带美丽；颜色纯正、明快的红、蓝、紫、粉红色；透明度好，即半透明；无裂纹、无砂心、无杂质；块重约0．5－2公斤者。
4、三级：纹带美丽；颜色纯正、明快的红、蓝、紫、粉红色；透明度好，即半透明；无裂纹、无砂心、无杂质；块重约0．5公斤以下者。

【玛瑙的灵性作用：】

1. 玛瑙是佛教七宝之一，自古以来一直被当为辟邪物、护身符使用，象征友善的爱心和希望，有助于消除压力、疲劳、浊气等负性能量。
2. 将适量的玛瑙放置于枕头下，有助于安稳睡眠，并带来夜夜好梦。
3. 玛瑙可以为一些的水晶饰品来消磁充电，如戒指、坠子、耳环、手链等，但请用纸或布包住，以免被刮伤。
4. 在西方魔法里，教人将自己的愿望写在一张纸上，折叠包妥，静心冥想过后，再放入玛瑙聚宝盆内，至少要放一天一夜，让能量在其中激荡强化，取出后，将之火化烧掉，藉助火的力量，将你的愿望传入自然界，多能心想事成。
5. 读书的小朋友多接触带水玛瑙，可以感染水的特性，聪明、灵活、乖巧、学习力强、适应力佳。
6. 戴着带水玛瑙，可以强化亲和力，能够灵活应变，八面玲珑，有助事业成长，财源旺盛。
7. 夫妻房中摆设带水玛瑙，有助于夫妻感情和睦，增进闺房之乐。
8. 玛瑙可改善内分泌，加强血液循环，让气色变好，消除性方面的障碍，避免性无能与不孕产生，偏橘色的红玛瑙则可对直肠，胃肠都有效用，可活化内脏，预防便秘，帮助排出毒素，对肝病、风湿、神经痛、静脉曲张等都有舒缓的功用，对于女性，长期佩带玛瑙可以是皮肤润滑，心情开朗，血液循环增强，使嘴唇红润，眼珠明亮有神。

No gemstone is more creatively striped by Nature than agate, chalcedony quartz that forms in concentric layers in a wide variety of colours and textures. Each individual agate forms by filling a cavity in host rock.

As a result, agate is often found as a round nodule, with concentric bands like the rings of a tree trunk. The bands sometimes look like eyes, fanciful scallops, or even a landscape with trees.Agate was highly valued as a talisman or amulet in ancient times. It was said to quench thirst and protect against fever. Persian magicians used agate to divert storms.

A famous collection of two to four thousand agate bowls which was accumulated by Mithridates, king of Pontus, shows the enthusiasm with which agate was regarded. Agate bowls were also popular in the Byzantine Empire. Collecting agate bowls became common among European royalty during the Renaissance and many museums in Europe, including the Louvre, have spectacular examples.

The mining of agate in the Nahe River valley in Germany, which was already documented in 1497, gave rise to the cutting-centre of Idar-Oberstein. Originally, the river was used to power the grinding-wheels. When the Nahe agate deposit had been exhausted, in the nineteenth century, Idar-Oberstein's cutters started to develop the agate deposits of Brazil, which sparked off exploration and the discovery of Brazil's rich deposits of amethyst, citrine, tourmaline, topaz, and other gemstones.

Although the small town of Idar-Oberstein is still known for the finest agate carving in the world, it now imports a huge range of other gem materials from around the world, which are then cut and carved in Germany and Asia. Cameo master carvers and modern lapidaries flourish along with rough-stone dealers who scour the world for the latest gem discoveries for export. And this entire industry sprang from that taste for agate bowls and ornaments during the Renaissance! Maybe agate is also a powerful talisman for success in international trade!