The Gregorian calendar's poem for October birthstones is another one that's kind of a downer -- see below:
October's child is born for woe,
And life's vicissitudes must know,
But lay an opal on her breast,
And hope will lull those woes to rest
Because many also believe opals to be bad luck, I'm going to give a nod in this post to an alternative birthstone for October, the Tourmaline. Note that I've covered Tourmalines in more depth in the post called 'T is for Tourmaline (Watermelon) Beads', so check that out too if you'd like more information on this wonderful stone.
Now back to the subject of Opals. The word opal comes from the Sanskrit word 'upala', for 'stone' or 'jewel'; it can also be linked to the Latin word 'opalus' for 'seeing jewel'. This gemstone is transparent to opaque, and is composed of silicon dioxide. Some exhibit rainbowlike hues that have a 'play of color' that vary depending on what direction the viewer sees the stone. The light passing through the stone shows itself as red, gold, green, and blue -- and this is known as its 'fire'. Precious Opals include various types and colors, including Black Opals which are more rare than White. Fire opals are orange and may lack the color play many jewelers seek. One of my favorite types is the Peruvian Opal (shown here in this lovely example from ccsdesigns01 on Etsy.com); I have several types available for sale on our own Etsy.com site at http://tinyurl.com/atcs2p3. Peruvian Opals are opaque and do not display the 'classic' fire, though they have a beautiful soft, dreamy blue appearance, with lovely brown highlights. Opals are generally found in Australia, the Czech Republic, Brazil, Peru, Mexico, southern Africa, and the United States.
The ancient Romans considered the opal a noble gem, second only to the Emerald. Today, many believe that the Precious Opal carries a seed of 'holy fire', an intense spiritual energy that consumes impure aspects of the self. White Precious Opal in particular is thought to be an emotional amplifier, intensifying not only positive states, but negative ones as well (which may account for its association with bad luck).
I leave it to you to choose which stone to associate yourself with (Opal or Tourmaline) if you were born in October. I have worn Opals most of my life and feel I've had an exceptionally lucky life -- so I don't personally believe there is any cause for concern in wearing them. On the other hand, as you can see from my post on Watermelon Tourmalines, that is one of my very favorite stones. So you may choose one, or you may choose to associate yourself with both! Whatever you do, you can't lose by wearing one or both of these beautiful gemstones, in my opinion.