This is an amazing, large cluster of many "tangerine" quartz crystals on granite from Madagascar. The entire plate is 14" long and up to 9" wide. The longest and largest crystal on the piece is about 4.8" from its base to the tip. There is beautiful coloration and sharp crystals on this spectacular plate with nice variety in crystal sizes.
These clusters are natural and not heat treated or coated. The orange color is due to a combination of Iron, Hematite and Manganese coating the surface of the crystals but may also be present as inclusions within the crystals themselves. A likely cause is a high iron content in the soil where these crystals are found.
Lower quality material often with lots of surface damage is present on the market from Brazil, but this is some of the first high quality, natural specimens I've seen from Madagascar.