When the three women are in the police department and Sara is explaining the clock diagram, the drawing on the chalkboard of the 'clock' changes shapes in between shots and the line at the bottom of it disappears completely as O'Riley is leaving the room.
When a gemstone fails to scratch glass, Warwick declares it to be "probably some cheap-ass cubic zirconia." A forensic scientist would know that, while not quite as hard as diamond, cubic zirconia is still 8 on the Mohs scale, harder than most semi-precious gems and perfectly capable of cutting glass, which has a hardness of about 6.
When Nick and Catherine are looking at Melvin Bennett's information, Nick says he was 70 years old. However, the birth year on the computer screen says he was born in September of 1931. This episode aired in February of 2001, which would have made him 69, not 70.
When Catherine and Grissom are discussing Terry Miller's arrival, Catherine is wearing an evidence tag that says "Foxy".