Other mistake: In the opening credits of the original broadcast, Kristin Kreuk's first name is misspelled as "Kristen." The credits sequence, which was new for Season 5, was corrected by the time the second episode of the season aired.
Other mistake: Lois' car has the plate number "AJH 927." This is the same plate number that Senator Jennings had on his car in a previous episode, "Exposed."
Other mistake: When he takes Lana to the Fortress of Solitude, Clark squeezes a rock and when he opens his hand we see a perfectly cut diamond. Problem here is that in the real world, diamonds don't come out of the earth already cut and shaped. (00:04:20)
Other mistake: Maddie and her father can control only glass, but when at the Talon he uses his powers to pull the diamonds out of the stained glass. Diamonds aren't glass.
Suggested correction: This may not necessarily be true by the way their powers work. Remember, diamonds are a form of rock that are clear. Glass is made from melted sand, which is a ground up type of rock that becomes clear. The similarities between diamonds and glass are enough that it is possible they could still do this.
Diamonds are compressed carbon, not a form of rock. Glass is melted silicon. They're both clear materials, that doesn't mean they're equivalent, otherwise they'd be able to control clear plastic or any number of other things too.
If more explanations of their powers were discussed in the show, one might be able to conclude they do or do not have power over diamonds. However, the script only states they have power over glass, they show no propensity for power over sand itself, or other rocks and minerals. As scripted, this remains as error as it go against what is established.
Other mistake: Jonathan Kent's headstone says he was born September 1, 1954. However, in "Relic", we learn Jor-El visited Smallville in 1961, where he met Jonathan's parents and his mom was pregnant with Jonathan. And we know it was him since Hiram (his dad) wanted to name their son Gene and Jessica corrects him and says his name is going to be Jonathan. Plus, if he was born in 1954, he would have been 25 when he won the high school state championship instead of a more realistic 18 if he was born in 1961.
