Fazenda Boa Esperança, Tauá, Ceará, Brazil
The emerald deposit is hosted in metasomatic biotite schists with phlogopite and talc. The emeralds are a associated with apatite and rare corundum (?). They are small (up to 2 cm long), light coloured, apple green. The emeralds often contain inclusions of biotite and phlogopite, molybdenite, tremolite, allanite, apatite and small gas-liquid inclusions, which considerably decrease the transparency of the crystals.Ref: E.Ya. Kievlenko (2003) Geology of gems, p. 94