Opal is a fascinating stone that can be tumble polished to create beautiful gemstones. This comprehensive guide will teach you everything you need to know about tumbling opal, from selecting the suitable stones to preparing them for the tumbler. We’ll also discuss the different types of finishes achieved with opal and show you some stunning examples of tumbled opals. So if you’re ready to learn how to tumble opal like a pro, read on!
What is the opal, and where does it come from
Opal is a hydrated amorphous form of silica, typically containing between three and 21% water by weight. It is classified as a mineraloid rather than a true mineral because of its amorphous (non-crystalline) structure. Opal is widely regarded as a gemstone and has been used in jewelry for centuries.
Opal is found in a variety of locations around the world, including Australia, Brazil, Ethiopia, Honduras, Indonesia, Mexico, and the United States. Due to their vibrant colors, Australian opals are particularly prized and often referred to as “fire opals” due to their vibrant colors.
Opal typically has a vitreous or waxy luster and may be transparent, translucent, or opaque. The most common opal colors are white, gray, yellow, orange, red, green, and blue. However, opals can also be found in many other colors, including brown, black, and even colorless.
Opal is rated a five on the Mohs scale of hardness, which means it can easily be scratched or chipped. However, opal is relatively soft compared to other gemstones, such as diamonds (rated a ten on the Mohs scale).
The different types of opal
There are two main types of opal: precious opal and common opal. Precious opal is the type of opal that is typically used in jewelry, and it can be found in a variety of colors. On the other hand, common opal is usually white or gray in color and is not considered as valuable as precious opal.
Precious opal is divided into three main types: white opal, black opal, and fire opal. White opal is the most common type of precious opal, and it typically has a light background color with darker colored patterns. Black opal is much less common, and its dark background color characterizes it. Finally, fire opal is the rarest and most valuable type of precious opal, distinguished by its vibrant red, orange, or yellow colors.
Common opal is divided into two main types: wood opal and potch. Wood opal is a common opal with a wood-like appearance and is typically brown or black. Potch is the other type of common opal, and it is generally characterized by its duller colors and lack of pattern.
Opal can also be classified according to its body color. Body color refers to the overall color of the stone, regardless of any patterns or markings. The three main body color categories of opal are white, light, and dark. White opals are the most common type of opal and typically have a pale background color. Light opals have a slightly darker background color than white opals, while dark opals have the darkest colors.
Finally, opal can also be classified according to its play of color. Play-of-color refers to the colors seen when the stone is moved in the light. The three main types of play-of-color are single, double, and triple. Single opals have one color seen when the stone is rolled, while double opals have two colors. Triple opals are the rarest, and they have three colors.
How to select opals for tumbling
When selecting opals for tumbling, it is essential to choose stones of a similar size and shape. This will help ensure that the rocks fall evenly and not get stuck in the tumbler. It is also a good idea to select opals with a smooth surface, as this will help prevent them from getting scratched during the tumbling process.
Preparing opals for the tumbler
Once you have selected the opals you want to tumble, it is time to prepare them for tumbling:
- You must clean the opals to remove any dirt or debris.
- You will need to sand the opals to smooth out any rough edges.
- You will need to soak the opals in water for at least an hour before tumbling.
Tumbling opal gemstones
After the opals have been prepared, it is time to start tumbling. First, you will need to add the opals to the tumbler along with some medium grit. Next, you will need to add water to the tumbler and turn it on. Depending on the desired results, the tumbling process can take anywhere from a few hours to a few days.
Once the opals have been tumble-polished, it is time to remove them from the tumbler. First, you will need to empty the tumbler and rinse the opals in water. Finally, you will need to dry the opals with a soft cloth.
Polishing opals with different finishes
After the opals have been tumble-polished, you may want to polish them with a different finish. The three most common finishes are high gloss, satin, and matte. High gloss is the shiniest finish and is typically used for jewelry. Satin is a less glossy finish and is often used for display pieces. Finally, matte is the minor polished finish typically used for cabochons.
Tips for tumble polishing opals
Here are a few tips to help you get the best results when tumble polishing opals:
- Start with medium grit and gradually move to finer grits.
- Add water to the tumbler regularly to prevent the opals from getting too dry.
- If using a rotary tumbler, add a small amount of oil to the opals to prevent them from getting scratched.
- Be sure to regularly remove the opals from the tumbler to check on their progress.
- If you are unhappy with the results, you can always start over with a different grit or finish.
- Start with inexpensive materials. If you are new to tumble polishing, starting with inexpensive opals is a good idea. This way, you can experiment without breaking the bank.
- Have patience. Tumble polishing takes time, so be patient and don’t expect overnight results.
Can all opals be tumble polished?
No, not all opals can be tumble polished. Opals that are too soft or fragile will not withstand the tumbling process. In addition, some opals may have inclusions that can be damaged by tumbling.
How long does it take to tumble polish an opal?
The time it takes to tumble polish an opal depends on the desired results. Tumbling can take anywhere from a few hours to a few days.
What is the best grit to use for tumble polishing opals?
The best grit for tumble polishing opals depends on the desired results. You will need to use a finer grit for a high gloss finish. For a satin finish, you can use a medium grit. And for a matte finish, you can use a coarse grit.
Do I need to polish my opals after tumbling?
No, you do not need to polish your opals after tumbling. However, if you want a different finish, you can always polish them with an extra grit or finish.
Can I tumble polishing multiple opals at the same time?
Yes, you can tumble polishing multiple opals simultaneously. Just be sure to add enough grit and water to cover all the opals.
Polishing opals can be a fun and rewarding experience, but it is crucial to understand the basics before getting started. More importantly, remember to take your time and experiment with different grits and finishes to find what works best for you. With a bit of practice, you’ll be able to create beautifully polished opal gemstones that shine like stars. Have you tried polishing opals yourself? What tips do you have to share?
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