Opal is deposited at a relatively low temperature and may occur in almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite and basalt. The word opal comes from the Latin opalus, by Greek opallios.The water content is usually between three and ten percent, but can be as high as twenty percent. Opal ranges from clear through white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Of these hues, the reds against black are the most rare, whereas white and greens are the most common. These colour variations are a function of growth size into the red and infrared wavelengths. Opal is Australia's national gemstone. Australia produces around 97% of the world's opal. Precious opal shows a variable interplay of internal colours and even though it is a mineraloid, it does have an internal structure. At micro scales precious opal is composed of silica spheres. These ordered silica spheres produce the internal colours and determines the quality of precious opal.
OPAL - foster love, passion, loyalty, faithfulness, emotional expressiveness, warmth, spontaneity and dramatic ability. Also associated with peace, and consciousness. A very emotionally responsive stone. BLACK OPAL promotes cosmic awareness and oceanic consciousness. BOULDER OPAL foster creativity and originality. FIRE OPAL inspires dynamic energy and intensity. SONOMA OPAL induces emotional stability. WHITE OPAL enhances competency and efficiency.
October modern birthstone: opal or tourmaline
Opal is a relatively soft mineral do not clean in hot water or in ultrasonic cleaner
Colour: AAA-grade is multicolour, AA-grade is blue /green, A-grade is red / green