Rainbow looking from the sky is circular.
I find it from the window of airplane.Seven beautiful circular rings is moving on the various white clouds.
Rainbow on the earth watched before is only a part of this circular ring.
After rain, I found a big half circular rainbow , and I was attracted to the double piled up rainbows from a school roof.
At that time, I could not see a closed circular rainbow.
Rainbow looking from the sky is accurately Sunbow .
Because rain falls down from a cloud, and never falls up to sky. I found "sun bow" in English dictionary, but no exact word in Japanese dictionary.
On the other hand, in Australia three primary colored rainbow is usual compared with seven colored rainbow in Japan.
A viewpoint of rainbow is a little different from Japan and Australia.

Opal is called as
"Fossil of Rainbow".
...
Flying beautiful circular ring "Sunbow" descend on the earth and the colors is mixed to a complicated fossil of sun bow in long time.
...
I thought it is well matched anecdote.
I do not care jewelry, but woman care about it.
I bought one to wife for a souvenir of journey .
A shopgirl explained about difference between white opal, black opal, and boulder opal, and more turn over the opals and gave me a lecture of a discrimination of triplet piled opal.
Jewelry have inscrutable complicated attractions.
In the word of Sanskrit , "UPALA" means jewelry.
That is ,
"OPAL" is a real jewelry.

It is well known Opal is a birth stone on October and means "Comfort".
Under the sun "Sunbow" flying over the white clouds and descend on the earth and have a long time with comfortable and changed to a fossil of sun bow.
After a long time humans dug out the "Fossil of Sunbow" and Sunbow is awaked by moving of hand to hand and finger to finger. A new travel looking for permanently comfort of Sunbow began.
On the half way of long way to heaven, I wish a long stay of Sunbow Opal as much as possible in our home with my wife.