What does "GEM BU" mean on a graded coin? 1 1

[writer1102]

Curiosity makes me ask this question:  What does "GEM BU" mean as far as a coin graded by NGC?  Here is an example:

https://www.ebay.com/itm/2012R-Vatican-50C-Pope-Benedict-XVI-NGC-GEM-BU-Vatican-City-Euro-Coin/283688105833?hash=item420d20f769:g:rt0AAOSwBqpd3AL6

Does it mean that the coin was not officially assigned an MS number?  Why would that happen?  Or does the coin pre-date current MS grading numbers?

Thanks!

[Ronnie@NGC]

Thank you for your message. 

Gem Brilliant Uncirculated (BU), or Gem Uncirculated, is an adjectival grade which NGC defines as being MS 65 or higher. The coin was not officially assigned an MS number, most likely as part of a special submission program. Adjectival grades exist alongside the numerical grades of the 70-point Sheldon Grading Scale.

[writer1102]

Thank you, Ronnie!