Mrkookm - I've noticed that when I kept these plants under higher lighting, they have a tendency to change colors! Some varieties turn a dark blue/green, or lighter green, it varies. You actually get a "sheen" effect in lower lighting as well, I think that in higher lighting the reflective pigments create a brighter "sheen" is perhaps why it is more visible in higher lighting. The common variety that is in the states at the moment, "brown" we call it here from western Kalimantan is a perfect example of this, it has a beautiful blue sheen whether in low or high lighting!