The gemstone is a pentagon which leads to the number FIVE
Their ability to produce mana should not be underestimated, as you dont normally get such a cheap Commander who can make so much mana (Rofellos is banned, after all)
Admiral Brass, Unsinkable Admiral Brass, Unsinkable promises to keep the pirate fun going well after they meet Davy Jones
Website : Tarkir: Dragonstorm MSRPs for Tarkir: Dragonstorm will be set as follows: Play Booster: $5.49 Collector Booster: $24.99 Commander Deck: $44.99 Bundle: $53.99 Important Dates : Full Card Image Gallery : March 28 : April 410 Tarkir: Dragonstorm Prerelease Events : April 8 MTG Arena Release Date Worldwide Tabletop Release : April 11 : April 11June 5 Magic Academy Standard Showdown : April 11June 5 Commander Party, Round 1 : April 1824 : April 25May 25 Magic Presents: Spring Flourishes : May 3June 1 Tarkir: Dragonstorm Store Championship Commander Party, Round 2 : May 1622 Tarkir: Dragonstorm Takes Flight at Your Local Game Store Looking to be among the first to play with cards from Tarkir: Dragonstorm
Snappy is another card that can be only found in retro frame in the set, with normal versions from previous prints found between $15-20
Twenty-one total Lessons is all I could find that was even a little bit playable, and of those, several wouldn't be if you had to put them in the main deck
