Tiny guest oriented inclusions with biotite crystal inclusions in a peridot from Myanmar

Tiny guest oriented inclusions with biotite crystal inclusions in a peridot (forsterite) from Myanmar

Thank you!

One of you asked us the question we were expecting (publication February 24th 2020 on Instagram)  about the following micrograph of peridot (forsterite):

"What are the short black needles in the photo?"

In fact, these are not needle-like crystals like rutile or hematite-ilmenite which are found in corundum for example.

They are simply very fine flat biotite crystals that are observed parallel to their plane and which, consequently, look like needles on a micrograph.

Forsterite Pyaung Gaung, Mogok, Myanmar.jpg

Figure 1: Inclusions of biotite from Pyaung Gaung, Mogok, Myanmar, observed parallel to their plane.

Forsterite, Pyaung Gaung, Mogok, Myanmar.jpg

Figure 2: Inclusions of biotite from Pyaung Gaung, Mogok, Myanmar, observed perpendicular to their plane.

 

  Thank you for following us and raising increasingly relevant questions on social media!