This is an International Gemological Institute (IGI) Colored Stone Report for a natural tanzanite gemstone. The report certifies that the stone is a natural zoisite (tanzanite variety), weighing 18.63 carats, cut in a square emerald mixed cut, and measuring 13.66 × 13.44 × 11.25 mm. It is described as bluish violet, transparent, with natural characteristics, and is classified as having a Tanzania origin based on current gemological information. The report also includes the gemstone's optical properties, approximate photograph, and notes that while tanzanites are commonly heat-treated, no indicative evidence of treatment was observed.