Notes:

Sugar's series bible timeline, taken from a very blurry image in the artbook. Some enterprising Redditors attempted a partial translation. Timeline appears to confirm that Lapis is the oldest gem, Jasper and/or Pearl are the second & third oldest (the way the paper is crumpled it's hard to tell which is the older one), Sapphire is fourth oldest, and is actually only slightly older than Ruby (by about a century or two). Garnet is 5,750 years old. Unsurprisingly, Amethyst is the second youngest Gem, while Peridot is the youngest.

"The new se___ble is custom delivered Pink" – the hell???