Rutile inclusions.  Slightly included Si2.   Inside mostly no inclusions to be seen with naked eye.  This is cobalt spinel from Luc Yen deposit.  Great offer here for collectors looking for an extremely rare type of blue spinel.   Natural unheated and fit to be set into a ring.
This is from Luc Yen Vietnam.   This deposit is in the same marble deposit that occurs in Myanmar Burma.   Luc Yen is only around 750 kms from the Man Sin deposit where the Jedi spinel came from.  I see a some calling dim burgundy red spinel Jedi which couldn't be further from the truth.  This is gorgeous looking spinel but it's not jedi it's just vivid red.   Jedi has a pinkish red glow.  This one is more like fine ruby.  
Luc Yen stones do not get treated.   No heat on the Luc Yen spinel.   Spinel do not respond to treatments like sapphire.  So rest assured this stone is 100% natural and untreated.   
Mined from under the rice fields in the alluvial gravels in the shallow valley near the original marble deposit.  Rubies and sapphire are also associated with this deposit similar to the Burma deposit.  I'm was a geologist before I became a gem enthusiast/gemologist.   My business plan is to bring the better quality gemstones to my customers at a better more fair price.