October’s Birthstone – Opal

October's Birthstone - Opal
1 year, 6 months ago 0

Opal is the official birthstone for October and the Zodiac sign of Libra.

How has opal been regarded in history?

The Aborigines of Australia say opals were formed as the Creator’s foot touched the earth when he came on a rainbow to give a message of peace to all mankind. The place where The Creator’s foot touched the earth the stones became alive, sparkling with all the colors of the rainbow.

Throughout history opal was believed to be the stone of good fortune.

  • Romans believed the opal held the  beauty of all precious stones
  • Romans called it the “Cupid stone” because it suggested the clear complexion of the god of love
  • Romans carried opal as a good luck charm or talisman to bring good fortune and Caesars gave their wives opal for good luck
  • The Arabs believed that they fell from the sky
  • Orientals referred to them as “the anchor of hope”. Lucky opal – the stone of hope

Today some people believe the opal promotes inner beauty, faithfulness, and eyesight. Opal is a stone of inspiration which enhances the imagination and creativity as well.

Where does opal come from?

Before the discovery of Australian opal in 1849, the only opal sources were in Hungary and South America. Although Australian opal did not appear on the world market until the 1890s, Australia now produces around 97% of the world’s opal: 80% from the state of South Australia. Given this, it is no surprise that opal is the national gemstone of Australia.

Other countries where opals are mined include Mexico, Brazil, the United States and some in parts of Africa.

Important characteristics of opal

The variety of natural opal is determined by the two characteristics of body tone and transparency.

  • Body Tone / color – Refers to the darkness or lightness  and color of the opal which may be colourless, white, through the various shades of grey, to black. 60% of the opal productions are white. Crystal opal or pure hydrated silica makes up 30% of the opal produced, 8% is black and only 2% is boulder opal.
  • Transparency – Opal may range from transparent to translucent to opaque. When natural precious opal is transparent to semi-transparent, and the colour clarity is sharp, it is often referred to as crystal opal.

 

Natural opals are usually described as boulder, dark/black, matrix and light. Play of color (or fire) may come in many patterns. Pattern refers to the physical structure and form of the play of color. One of the attractions of opal is its amazing play of spectral colours unique to this gemstone. This originates from the breaking up of white light due to the three dimensional spherical shaped microstructure of the silica particles in the opal.  The effect is similar to oil lying on water or the play of light giving rise to a rainbow.

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. When used to make jewelry this gem’s natural color is often enhanced by placing thin layers of opal on a darker stone.

 

How is the value of an opal determined?

The value of an opal is determined by the type of opal, the predominant colours it exhibits, the clarity or brilliance of these colours and the patterns in which the colours are arrayed. Good patterns of the diffracted colours have a significant impact on the value of the opal. The most common patterns are pinfire and flake fire which look like tiny pinpoints or small flakes of color. Distinct patterns such as rolling flash, straw pattern, Chinese writing, ribbon, and especially harlequin, are very rare and considered collectors’ items. Precious opal shows a variable interplay of internal colors.

 

Precious opal

Common opal

 

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