Dimensions: 6.88 x 4.98 x 3.46 mm

Fire Opal gemology
Species: Opal
Color: Yellow to orange
Chemical composition: SiO2 .nH2O hydrous silicon dioxide
Crystal system: Amorphous; kidney- or grape-shaped aggregates
Hardness: 5.5-6.5 (Mohs scale)
Specific gravity: 1.98 - 2.50
Refractive index: 1.37 - 1.52
Birefringence: None
Optical character:
Color of streak: White
Absorption spectrum: 700 - 640, 590 - 400
Fluorescence: greenish to brown