This is a list of the cursed jewels discussed by Matthew's Video. The camera quality sucks and the pencil writing is too light... I'm sorry -_-
Here's what it says to those who can't read that and those who didn'tbwatch that video.
1. Blue Star Sapphire (Star of India)
2. Red Spinal (The Black Prince's Ruby)
3. Blue Diamond (Yes, it's a blue diamond)
4. White [with pale blue tinge] Diamond (The Regent)
5. White [with yellow tinge] Diamond (Shah Diamond)
6. [Pale] Yellow Diamond (Sancy Diamond)
7. Purple Sapphire (Delhi Purple Sapphire)
8. Black Diamond (Black Orlov/Eye of Brahma) - 3 pieces cut
9. White [Colorless] Diamond (Koh-i-noor Diamond) <---Leader
10. [Deep] Blue Diamond (Hope Diamond)
--------------------------------------------------------------------------------------------------------------------------------
Keep in mind that these jewels are founded in/looted from India [except for Star Sapphire, Sri Lanka]. So the designs of their SU form should be influenced by its culture. Like I said, I might try it but I give this task as a challenge.
Side note: I headcanon that there is a difference between cut and shattered, shatter means being gone completely while cutting a gem will created more forms (like starfishes) and are considered as separated beings. In case of Black Orlov, if the three pieces bond together, think of The Holder series(except nothing happens)
I call these gems 'The Cursed Court Jewels', and I see them gloomy in public since they brought disgrace to their colonies but when they are in private, they are happy for being a colony nobody asked for.