You sacrifice these to "impulsive draw," which is where you exile the top card of your library and play it for the rest of the turn
This widespread play, combined with the cards limited availability, has pushed it into the $20 range on the secondary market
Harmonic Prodigy was made for this deck since your commander is a wizard itself, and there are other wizards/shamans in the list
Expansion symbols of different rarities (colors) are considered the same symbol
Hall of Gemstones is incredibly disruptive for most decks with two or more colors and will force your opponents to be very careful about how they use their mana rocks
[1] Sorting operations [edit] Multiple column sorting was commonly done by first sorting the least significant column, then proceeding, column by column, to the most significant column