知识文 | 含有典型孪生方解石包体的抹谷红宝石

“在未经加热的缅甸红宝石中包含的方解石晶体，会显示出引人注意的孪生平面。”

“An included calcite crystal within an unheated Burmese ruby displays dramatic twinning planes.”

未加热的缅甸红宝石在交叉偏振器间观察到的孪晶平面方解石晶体。

缅甸抹谷是世界上最著名的红宝石来源之一，该产地的红宝石通常伴生于方解石—大理石矿石中。

The Mogok Stone Tract in Myanmar (formerly Burma) is one of the world’s most famous sources of ruby, which often forms there in a calcite-marble host.

方解石可以作为红宝石内的夹杂物出现，如上例所示。在这颗红宝石中，方解石很容易在交叉偏振器之间发现，这揭示了“十字形”晶体的多合成孪晶平面。

Calcite may occur as an inclusion inside the ruby, as in the example above. In this stone, the calcite is easy to spot between crossed polarizers, which reveal polysynthetic twinning planes that “crisscross” the crystal.

虽然方解石是红宝石中的常见包含物，但图片中的是本文作者所见的方解石孪晶最明显的例子。方解石晶体周围是一个密集的，有角度的嵌套短针金红石丝绸巢，这是该产地的红宝石的典型场景。

While calcite is a common inclusion in ruby, this is the clearest example of calcite twinning this author has seen. Surrounding the calcite crystal is a dense, angular nest of exsolved rutile silk as short needles, a typical scene in rubies from this locality.