First of all, thank you, Colum, for a fantastic month of reviews. There were some great puzzles last month, including yesterday's, but things are looking good for August too, if this fine offering from Mr. K. A. Collins is any indicator. It starts out well enough with GEMSTONE (1A: Rock), a nice modern definition of the clue. HBOMBS (9A: Big releases of the '50s) is ok, and I only learned the term LADMAG (18A: Maxim, e.g.) from puzzles, but things really pick up once we get into the middle section. BABYCAKES (27A: Sweetie) contrasting with FRIENDZONE (32A: Relationship with unrequited love, in modern slang) is lovely. TONGUETIED (36A: Stammering) is great.
In the SE, we have the amusing 40D: "____ says..." (SURVEY), and QUITS (42D: What you might call it). SABLE (40A: Shade of black) is an elegant word, and PASYSTEM (56A: Principal means of address?) puts this reviewer in mind of Principal Skinner, and that's never a bad thing.
FREEUNION (32D: Cohabitation without marriage) feels a little arbitrary. Is that a thing people say? Didn't we used to just say "Living in sin?" Heh. Sin.... And I don't particularly love some of the threes in this one. GPO (1D: Mail ctr.)? I guess it's short for "General Post Office," but it's not a thing I know. NGO (49D: CARE, e.g., for short) is non-governmental organization, right? Why don't we just call those things "organizations?" GTS (37D: Some high-speed cars)... meh.
But really, these are things that I will tolerate happily for the rest of the grid. Overall, I really liked this one. Here's hoping it's an auspicious omen for the rest of the month!