Opal’s patterns of rainbow-colored brilliance change
depending upon the viewing angle, an important component
of the Mexican opal's beauty.
Some of the opals from Mexico exhibit a
beautiful play-of-color effect, showing patches of red,
orange, yellow, and green when polished as cabochons.
Those with a bluish body color are called "water
opal," and orange-colored ones are referred to as
"fire opal." The Aztecs, whose civilization
flourished in modern-day Mexico from the mid-14th century
until 1520, used opals in their jewelry. Development of
the Mexican opal mines was renewed in about 1850.
Mexican opal's beauty lies in how the brilliant
patterns of colors seen in these highly transparent gems
change with the viewing angle. In water opal, it appears
as if the flashes
are trapped in clear water; in fire opal, they appear
to be trapped within a flame. The patches of color generally
become weaker in more transparent stones, and high-quality
pieces are rare gems that manage to combine these opposing
Around 1960, there was a surge in the popularity
of Mexican opals, and Japanese consumers were especially
fond of them. At the time, its popularity in Japan was
said to be surpassed only by that of diamond, ruby, and
However, Mexican opal's marketability suffered
after 1970 because of repeated cases where cracks developed
due to a loss of water content. Details varied widely,
with some stones developing cracks immediately after being
polished, others after a few years of use, and so on.
These days, rings set with Mexican opals are often brought
in for remodeling or remaking, a fact that attests to
the popularity once enjoyed by these gemstones.
polished Mexican opals are reappearing in the marketplace,
though on a small scale. The opal miners know which exact
spots produce the best material, and rough stone prices
reflect this. Cutters who are concerned with their reputations
buy rough material that they know will not develop cracks,
and polish them only after confirming their quality over
a period of three to four years. This is another example
of how "who you buy from" is more important
than "what you buy" when it comes to gemstones.
It is important to wear Mexican opals
to give them natural moisture. When cleaning opal jewelry,
it is best to use a soft brush with mild soap; avoid ultrasonic
The shops in Cabo San Lucas and San Jose del Cabo offer
a fascinating and tempting array of these gems.