White Opal Ring
Opal, one of my favorite gemstones, is a mineraloid gel made of a combination of tiny silica spheres about 1000th of a millimeter in size, and water. Water content ranges from 2-3% to as much as 30%. In precious opal the lattice arrangement of the spheres causes interference and diffraction of the light striking the stone, hence the “play of color” that makes opals so beautiful. Australia produces over 95% of the world’s opals.
Leave a Comment August 26, 2010
Buying a custom piece of jewelry can be a daunting task, since most people are uninformed about gemstones, precious metals, or what even makes a quality piece of jewelry. The best advice I can give is to spend some time to educate yourself. There are many sources of information in this internet age, but they can be very confusing. I recommend John Leonard Studio as one source.
Look for a jewelry professional who is willing to take as much time as necessary to teach what you need to know to make a truly informed purchase. Ask questions until you can’t think of any more to ask. Remember that there are no “dumb” questions.
When purchasing a valuable piece of jewelry you should buy from a professional who you feel you can trust. A true professional has your best interest in mind, not just the sale. After all you are buying adornment that, if properly taken care of, will last a lifetime, and can be a gift to your heirs.
Leave a Comment August 26, 2010
The origins of “lost wax casting” are somewhat shrouded in the mists of history. Most scholars see the Middle East in the area of Mesopotamia as the earliest place which used the process, specifically the Sumerians. Some, however, think India may have been the first. There is historic evidence that shows metal casting being done in India around 3500BC and by the ancient Egyptians as early as the mid third millennium BC. The process was used by the Greek, Romans, Aztecs, Incas, Mayans, Chinese and more. Bees wax was a common modeling substance and investment in ancient times was the local clay.
Leave a Comment August 7, 2010
Since about 75% of my work is produced through “lost wax casting” people often ask me (really they do) just what exactly “lost wax casting” is. With out going into too much detail, the process is really rather simple as it applies to jewelry.
First a wax model is made of the object to be cast is made.
That wax model is placed in a steel tube called a flask with a rubber cap that has a bump (button) to which the wax model is attached.
The flask, now closed on one end by the cap, is filled with slurry called investment, not unlike plaster of Paris. (“Lost wax casting” is also more properly called investment casting.)
This investment has ingredients that allow it to be heated to high temperatures. When the investment hardens, the rubber cap is removed and the flask is placed in a burnout oven (kiln) and slowly raised to 1350 degrees Fahrenheit. During this process the wax melts and flows out of the investment, hence “lost wax”. What remains is a negative space in the shape of the original wax model. It is into this that molten silver, gold or other precious metal is poured and a rough casting is produced.
When the investment is removed the casting is finished and polished.
And there you have a very simplified explanation of lost wax casting.
I wish you all could see the molten gold in the crucible…it’s pure alchemy.
5 Comments August 7, 2010
The hardness of a mineral, in our case gemstones, is typically measured by its ability to scratch another material. A material higher on the scale can scratch those below it. The scale from 1 to 10 was created by Friedrich Mohs in 1812. At the top of the scale in natural gemstones is the diamond at 10 and at the bottom would be a material like graphite (pencil lead) at 1 on the scale. Other common materials along the scale are gold and silver at 2.5 – 3, steel at 4.5, quartz at 7, and rubies and sapphires at 9. Remember that just because a diamond is at 10 on the Mohs Scale doesn’t mean it can’t be smashed to smithereens by a steel hammer (4.5 on the scale).
Leave a Comment July 26, 2010
