Phlogopite is found in matrix on marble and calcite usually. The marble is not fluorescent, but the calcite pieces are very nice - offering a striking pink/red background for the bright yellow fluorescing phlogopite crystals. Many of the crystals on this piece are nicely gemmy. On this specimen the phlogopite is bright yellow under SW UV. The calcite fluoresces under both SW and MW, but is brightest under MW. Displaying it under both lights offer the best color (first pic). The longwave pic is shown just for interest - a dull white fluorescence.