Nothing Lost In Translation

Coober Pedy is one of those odd Australian place names. It’s a famous opal mining town. The name was given by the Aborigines. It means “white man in a hole.”

I wonder what some of our local Indian names mean.

Literal Translation

 The Greek word for amber is electron. Amber, naturally hardened tree sap at least one million years old, produces static electricity when rubbed with a cloth. The German word for amber is bernstein, the stone that burns. Amber burns with a distinctive natural odor. One way of distinguishing amber from its plastic imitation is to carefully touch the stone with a hot needle and smell the resulting smoke.

Old Miner

The picture above shows what is called an old mine diamond. As you can see, it's pretty crude. It looks like it was hacked out by Conan the Barbarian.

A mathematical analysis of the opti-mum angles and proportions to give maximum brilliance by a Belgian named Marcel Tolkowsky in 1919 paved the way for the modern cut diamond in the 1920's.

Before that, most diamonds looked like the one above. The black hole in the center of the diamond is a large flat on the bottom instead of a point (called the culet). The three black spots on the left are reflections of it in the too-steep crown (top part of a diamond).

As you can see, the diamond is squarish, rather than round and its asymmetry is common in old miners.

Old mine diamonds do not have very good brilliance due to their poor proportions, and are valued as recut candidates.

An old European diamond is like an old mine diamond except that it is round. Old European diamonds suffer from the same defects as old mine diamonds: large culet, shallow bottom, tiny table facet, and very steep crown.

How To Clean Silver

Silver reacts with sulfur compounds in the air and tarnishes. First it turns yellow, and then black. Tarnish is not dirt, and dirt must be cleaned off with jewelry cleaner or soap and water before you remove the tarnish. Silver cleaner, liquid or paste, is designed to remove tarnish, and it does so almost instantly. Never soak silver jewelry in silver cleaner for more than a few minutes (an overnight soak will turn it black). After removing the item from the silver cleaner, flush thoroughly with water. If the chemical is not removed from all the nooks and crannies it will bleed out over time and leave black streaks.

Do not immerse soft gems like coral, shell (mother-of-pearl, cameos), pearls, malachite, or turquoise in silver cleaner. Dip the corner of a paper towel in the silver cleaner and paint around the stone. Marcasite will not be harmed by silver cleaner, but be careful if the jewelry is antiqued, i.e. blackened in the recessed areas. Antiqued items should be dipped for only a few seconds and then rinsed off immediately or the silver dip will remove the black and leave an unsightly greyish-white color. A concoction called liver of sulfur (yuck!) will restore the finish.

Sometimes, if the tarnish layer is thick, the silver underneath will have become depolished and will look greyish-white. Then the piece will have to be polished on a buffing machine by a jeweler. Discoloration caused by contact with chlorine compounds (bleach or swimming pool water) will not be removed by silver cleaner. The jewelry will have to be buffed on a wheel.

For jewelry with smooth surfaces and not many nooks and crannies, a silver polishing cloth will shine it up. Also, dry baking soda rubbed over the piece with thumb and forefinger or a dry toothbrush will shine it. You can make an old penny into a new penny this way with about 45 minutes of hard work. Flush thoroughly with water when you are done or the piece will turn black.

The Real and the Fake

The two photos below are of a garnet and glass doublet, a stone that was often used to imitate other gems before the advent of modern synthetics. I still see them in old jewelry that customers bring in.

Garnet is the only gemstone that will fuse directly to glass, without glue. The garnet top gives this imitation higher luster and more durability than glass. Even though the garnet is red, it’s only a thin sliver and the stone takes on the color of the glass, which can be any color. Usually the garnet covers just the table, the large flat facet on top of the stone, not the whole crown, or top of the stone. In the right photo, the arrow points to the ragged border of the garnet slice.

What makes this photo so interesting are the classic needle inclusions in the garnet, shown in the close-up at left. This little bit of garnet exhibits a profusion of oriented needles that are diagnostic for red garnet. The needles are of a mineral called rutile that formed inside the garnet and lined up with its crystal structure. Needles in the same plane cross each other at 70º and 110º .

Also present are a lot of gas bubbles, the dots in the photos, which, in close up, have a distinctive appearance, formed by trapped air in the fusion plane between the garnet and the glass.

Gas bubbles always indicate some sort of fakery; they do not occur in natural gems, except amber, obsidian (volcanic glass), and moldavite, (meteoric impact glass). So this garnet and glass doublet shows the real and the fake together.