Thanks to everyone who responded to my request for info on Titania
stone. An hour after posting the query I came across an article in
Time magazine archives dated Monday, Feb. 26, 1951. Note: Check out
the price of "first-grade white diamonds"
The link to the article is:
Monday, Feb. 26, 1951
In some respects, the new "diamonds" made of titania (titanium
dioxide) are better than the real thing.86 Last week three
advertisements in the New York Times Magazine offered cut stones
"more brilliant than diamonds" at prices ranging from $10 to $16 a
carat (price of first-grade white diamonds: about $1,100 for a
one-carat stone). One ad suggested: "A handsome engagement ring made
of our remarkable gem presented to any girl will win her devotion.
The hundreds of dollars saved will go far toward building a
Titanium dioxide is found in nature in black or brown crystals known
to mineralogists as "rutile." When the pure oxide, finely powdered,
is fed through an oxyacetylene flame, it collects in a solid,
carrot-shaped "boule." At first the boule is black, but careful
heating turns it to a very faint yellow, the color of good-quality
"Cape diamonds." Stones of almost any color, including blue, green
and deep yellow, can be made by doctoring the oxide with small
amounts of impurities.
Titania's close resemblance to diamonds is due to its index of
refraction, i.e., its ability to bend light rays. This property makes
a stone glitter. Diamond's index of refraction is extremely high:
2.42. Titania's index is higher: 2.62 to 2.90. Even more important is
its "dispersion," i.e., its ability to break white light into rainbow
colors. Diamond disperses light twice as much as common glass does,
but titania disperses it seven times as much. So far, titania cannot
be made absolutely white (many valuable diamonds are not white,
either), and it will never rival diamond in hardness.
Those who cherish diamonds because of their high cost (owing to the
tight control of the South African diamond monopoly) will not welcome
the development of titania. But in sparkle and "fire," it surpasses
its rival and may force the merchandisers of genuine diamonds to warn
their customers against too much "fire."
86Synthetic sapphires and rubies are made artificially of aluminum
oxide, are therefore the same chemically as their natural
counterparts. Natural diamonds consist of carbon, so gems of titanium
dioxide cannot be called "synthetic diamonds."
Silversmith and Lapidary Artisan
Rocky Mountain Wonders
Colorado Springs, Colorado