What do these mineral classification symbols mean?
In addition to being a non-practicing chemist, I'm also a non-practicing geologist, so look no further for an answer you can trust.

Your minerals are classified as follows: C is for color (sample, gross), S is for streak (color of powdered mineral, essentially, on an unfinished streak plate), H is hardness on the Mohs scale, SG is specific gravity, L is luster, and CL is cleavage (how the sample breaks along planes dictated by the crystal habit of the mineral). See this reference for a printable chart.

The color-coding is certainly used to mark the samples in case they get jostled or mixed up and need to be matched to their appropriate slots: those codes are not related to the mineral classification.