Deokaran Saraogi & Sons

It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. Opal is the birthstone of October.

Opal is a unique mineraloid composed of hydrated silica (

SiO2⋅nH2Ocap S i cap O sub 2 center dot n cap H sub 2 cap O

2⋅2

) with 3% to 21% water content. Famous for its dazzling "play-of-color" (opalescence), this gemstone displays a rainbow-like spectrum that shifts with movement. It is relatively soft, rating 5.5–6.5 on the Mohs scale of mineral hardness, and is primarily sourced from Australia and Ethiopia.