Archive for the Chalcedony Category

Agate

Refractive Index : 1.54 – 1.53

Optical Characteristic : AGG

Specific Gravity : 2.60 (+0.30 – 0.05)

Formula : SiO2

Crystal System : Trigonal

Variety/Species : Chalcedony

Species/Group : Cryptocrystalline Quartz

Birefringence : .004

Dispersion : None

Hardness : 6.5 to 7

Toughness : Good

Ultrasonic : Usually Safe

Steam : Usually Safe

UV Long : Inert to moderate

UV Short : Inert to moderate

Pleochroism : None

Strength : N/A

Pleochroism [...]