17" 5 station necklace E. King

I’ve had this necklace for a few years. Wondering about the origin of the turquoise. I’m not sure whether the cabs have changed color or it is by design that the two outer are darker, the next two lighter and the center stone the lightest. Or if they have changed color due to perfumes & etc.

What I know is it is marked as 12 kt gold filled and E. King used this particular hallmark between 1978 - 1983. It is unusual, curious about a value. There are 56 beads, about 1/4". The findings are hand made. Center cab sized 5/16" x 3/8"; 2 side cabs are 1/4" x 5/16"; 2 outer cabs are 1/4" x 1/4"

This would be enhanced Kingman. It use too be easy to get your hands on, now not so much. Beautiful piece.