Ally tries to call Albert later, but she gets a message that his number isn't in service. She hopes he hasn't moved. She's relieved to see him on Monday and asks him if it's true that touching a butterfly's wings kills it. Albert says it isn't true and Ally is so relieved, she hugs him. She thinks his surprised expression is hilarious.
Albert's number being out of service is likely another indicator of his family's poverty, while Ally's thought that he may have moved shows that she's still naïve when it comes to what living in poverty actually means and entails.
Later at lunch, Shay compliments Albert's Flint shirt and explains that she got a new sweater that's purple, the color of royalty. Ally doesn't know what to say, but Albert confirms that purple is a royal color. Shay says that Albert and Ally are uncouth and asks if Ally even knows what "uncouth" means. Albert says that only an uncouth person would wear snail snot and goes onto explain that the color purple used to come from snail slime. In medieval times, it took three thousand snails to make one purple cloak. Albert and Ally agree that they'd rather wear beige, and Ally smiles at the disgusted look on Shay's face.
Even though Ally and Albert use this fact about snail slime to pester Shay, the fact also makes a good point: that something can be small and be considered gross, but still be extremely important, valuable, and a marker of royalty and class. By asking Ally to participate in talking about the merits of snail slime, Albert also gives Ally a safer place to practice standing up to Shay, which in turn can help Ally become more confident.