WHO MADE THIS RUBY?

Which giant drill has the natural diamond, and which the synthetic? You would hardly be expected to know. But these days you would have to carry a microscope to tell if a lady is wearing a real ruby brooch, or a real emerald pendant, or even a real star-sapphire ring. "It is practically impossible to see the difference between the natural and the synthetic gems," states a chemist. "The structure is identical. Even an expert must study the crystals under the microscope to spot tiny differences." Successful duplicates of rubies came long before the first triumphs with diamonds. Back in 1904, a French chemist named Auguste Victor Louis Verneuil produced synthetic rubies in a very hot furnace. Although some improvements have been made since, the same process is still in use today.

Like diamonds, rubies and sapphires are also forms of a cheap and plentiful substance. In this case it is a mineral called "corundum." The coarser forms of the mineral are used for grinding or polishing; the finer ones are the jewels.

The synthetic gems are produced by making the mineral in its crystal form. Corundum consists of aluminum oxide. Scientists can create aluminum oxide by heating pure alum, which is an aluminum compound. In order to produce a ruby, the chemists add coloring matter made out of a chemical called "chromic oxide."

"When synthetic jewels first appeared I used to figure that if a lady was wearing a gigantic ruby it could not be natural," says one observant young man. "After all, how many people can afford to buy a ten-carat stone? The Aga Khan and Princess Grace of Monaco. But nowadays, people have caught on to that, and buy small synthetic gems, too, which are just about foolproof."

Giving the chemist's battle cry, "Anything that exists in nature can be reproduced in the laboratory," scientists have tried their skills at producing star sapphires and star rubies. These are crystals which appear to have a star in the center. They are extremely rare in nature. As a result, they are so valuable that for many years most of the buyers belonged to royalty.

A child observing a star sapphire on display in the window of a jewelry store turned to her mother and said: "It's so beautiful it must be fake."

As the year was 1937, the youngster could not possibly have been right. Ten years later such a remark might have been the truth.

A successful way of making the star gems was found in 1947. The first step is to make a plain synthetic ruby or sapphire. This is then used as a seed on which the star gem is grown. Synthetic star sapphires are not yet as large as the natural. The greatest of these gems found in nature weighs 563.35 carats; the biggest laboratory duplicate, 35. On the other hand, size is no problem when it comes to turning out synthetic star rubies. The largest known natural star ruby weighs 102 carats. A 109-carat star ruby has been made in the laboratory. Of course not many people could wear it.

Today the Linde Company, a division of Union Carbide Corporation, makes four star stones: the star sapphire, star ruby, white star and black star.

The accomplishment of which scientists are most proud is the production of synthetic emerald. It is extremely difficult to make this gem in the laboratory. This was first done in 1930 by the German chemical company 1. G. Farben. The technique used there has remained a carefully guarded secret, but Americans have worked out equally successful methods since then. Emeralds are a form of the mineral beryl. The emerald is grown around a crystal of colorless beryl, which serves as the seed. Coloring matter made out of chromium is added to produce the brilliant green color known as emerald.

In ancient Egypt emeralds were a sign of wealth, much as they are today. And just as now, those struggling along on less than a Pharaoh's income had to make do with imitations. These, to be sure, bore only a general resemblance to the real emerald. The age of the synthetic jewel was still thousands of years in the future.

In addition to making emeralds, rubies, sapphires and diamonds, scientists can reproduce almost any gem you might name. Garnets, for example, are precious stones which are not so precious as all that. They are, in fact, often used as imitations of other more valued gems. But they, too, can be made in the laboratory.

During the period when research on synthetic diamonds was at a standstill, a weary scientist took some time off. Just for a change, he had a try at making garnets. He took some hornblende, a fairly common mineral ore which contains most of the same elements found in natural garnets. This ore was subjected to a pressure of 441,000 pounds to the square inch and a temperature of 2192°F. Sure enough, garnets emerged from the pressure chamber. However, as garnets are not particularly valuable, his discovery did not receive the praise given him a few months later when the same general process yielded diamonds.

Synthetic gems sell at prices that average between one-tenth and one-twentieth of the cost of the natural, so it is not surprising that business in synthetic jewels is increasing by leaps and bounds.

"The only thing that holds us back is that word 'synthetic,' " says a jeweler sorrowfully. "You can't get anybody to say `synthetic diamonds are a girl's best friend.'"

Not all of these man-made jewels are set in tiaras, bracelets, brooches and necklaces to be worn by glamorous women. These gems are as useful as they are beautiful.

"We make as many crystals for industry as we do for jewels," reports a spokesman for the Union Carbide Corporation.

Rubies and sapphires are very hard, second only to diamonds. They can survive a lot of wear and tear. Rubies are placed in the bearings of expensive watches; ball point pens may have ruby points; phonograph needles are frequently made of sapphire. Both gems hide their fire when set in a number of machines, such as tape recorders or thread guides for textile mills.

The electronics industry uses rubies and sapphires. Microwave and vacuum tubes and other electronic equipment often contain sapphires. Rubies are particularly valuable in the field of communications. They can send beams of light across distances as great as a million miles. Information can be carried on these light waves. The device that is used is called an "optical maser." You will be hearing a lot about it in the space age ahead.

"One of the synthetic crystals used in masers to communicate with outer space is an almost unbelievable combination - ruby on the outside and sapphire on the inside!" reveal Union Carbide officials.

Is there life on other planets? What are conditions on the surface of the moon? The ruby and sapphire will help to bring us answers to these questions.

(From The artificial world around us, by Lucy Kavaler)