Jewelry Blog

October Birthstones

infographic titled October Birthstones featuring opal and tourmaline

October doesn’t just have one birthstone, but two. The first of the October birthstones is the opal, and the second is the tourmaline. What these two birthstones have in common is that they both have the widest and most diverse color ranges in the world of gemstones. What’s more, they not only occur in uniform colors but in a variety of color combinations. 

In this article, we’ll tell you everything you need to know about these two October birthstones.

What are the Birthstones for October? 

infographic titled October Birthstones  featuring opal and tourmaline

Two gemstones represent the month of October: opal and tourmaline. Both of these birthstone options are famous for containing a lot of color choices. 

Opal is a mineraloid, a type of hydrated silica. In other words, opal has a certain amount of water in it (from 6 to 20%). Main geographic sources of opal include Ethiopia and Australia. There are two types of opals – precious and common. Precious opals can display iridescence, otherwise known as a play-of-color. This gemstone can be translucent, transparent, or opaque, and it can appear in almost any hue, from different colors of the rainbow to gray and black. 

Tourmaline is a silicate mineral that consists of crystalline boron. It can contain concentrations of iron, aluminum, magnesium, potassium, lithium, and sodium. Since it can have a combination of all these elements, tourmalines virtually occur in almost every color, from bright red to colorless. In fact, tourmalines display more colors and color combinations than any other gemstone. They typically come from metamorphic and igneous rocks mined in Brazil and Africa. Unlike opals, which form in low temperatures, tourmalines usually form by hydrothermal activity and hot temperatures. 

Both these October birthstones are quite popular and make beautiful pieces of jewelry. While they are an affordable alternative to diamonds and pricier precious stones, they can still command high prices as well. 

Myths and History of October Birthstones

Myths About the October Birthstones infographic featuring ring and stone images

The usage of opals, as well as people’s deep appreciation for them, can be traced back to Ancient Rome. Since it can display a wide variety of colors at once, opal’s connotation was always related to magic, mental strength, and the supernatural.

Due to their colorful properties, opals have an association with volcanoes, the moon, lightning, fireworks, constellations, and galaxies. They served as an inspiration to writers, poets, and painters, and were especially favorable to royalty. It’s even the national gemstone of Australia. Today, opal is a symbol of purity, hope, and abundance. 

The name tourmaline means “unknown gemstone of mixed colors,” a term that comes from Sri Lanka. Tourmalines have been mistaken for other colorful gemstones for centuries. Since they occur in virtually any color, people thought they were emeralds, rubies, sapphires, and other gemstones. It wasn’t until the 1800s that tourmalines were classified as separate mineral groups. For example, a recent discovery brought proof that some of the famous Russian crown jewels were, in fact, tourmalines and not rubies. 

Interesting Factoid: The first-ever tourmalines were thought to be “Brazilian emeralds.” 

What sets tourmaline apart from all other colored gemstones is that it can be electrically charged. Due to its pyroelectric properties, it earned the nickname “the Ceylonese Sri Lankan Magnet.” The most common tourmalines are black.

Tourmalines can represent several different meanings, mainly depending on their color. For example, pink tourmaline is a symbol of compassion and affection, while red tourmaline represents wisdom and strength. Whatever the color, many believe that tourmalines have mental and physical healing properties. Some even thought that the colorful tourmalines came from rainbows.

Mining Locations of Opal and Tourmaline

Where Does Opal and Tourmaline Come From infographic with map image

The main sources of opal are mines in Australia and Ethiopia.

Australia, specifically, has produced up to 95% of precious opals in the whole world. In fact, opal is the national gem of Australia. 

The Australian mine that produces the majority of opals is Coober Pedy. The Coober Pedy is the mine of the largest opal discovery, the Olympic Australis. Weighing approximately 17,000 carats, this single opal has a value of AUD$2.5m. 

Aside from Australia and Ethiopia, opal deposits mines are in the Virgin Valley in Nevada, the Czech Republic, Mexico, Indonesia, Canada, Idaho, Slovakia, Turkey, Brazil, Hungary, and many other places. 

Rock opals can occur almost anywhere, including sandstone, limonite, marland, basalt, and rhyolite. 

The main source of tourmaline is Brazil, which has a record of producing tourmalines in almost every color. Other mining locations of the tourmaline include Maine, Nigeria, California, India, Mozambique, Sri Lanka, Tanzania, Indonesia, Kenya, Malawi, Namibia, Madagascar, Pakistan, and other countries. All these deposits produced tourmalines of different colors. For example, the tourmalines that come from Maine are either pink or green. Californian tourmalines have a combination of these two colors, otherwise known as bi-colors. 

A new and recently found type of tourmaline called Paraiba tourmaline mainly comes from Brazil. They’re bright blue and bright green, and experts consider them to be the most valuable type of tourmaline. 

Physical Properties of Opal and Tourmaline

Properties of Opal and Tourmaline graphic with Mohs Hardness Scale values

Physical Properties of Opal

What makes opal unique is the play of color that it displays on its surface. This phenomenon occurs due to grids of microscopic silica spheres, which are only 0.2 microns in size. The diffraction of light causes it to change colors depending on the angle you’re viewing it from. Opals that have this ability are called precious opals. Common opals, on the other hand, naturally have an opaque “hazy” color, with bluish or greenish hues. They’re also known as “milk” opals. 

Another interesting fact about opal is that it contains water in its silica structure. It can contain up to 20% water, making it softer than other gemstones. In fact, opal has a hardness from 5.5 to 6.0 on the Mohs scale. 

When it comes to color, opals can occur in a myriad of colors at once, making them truly unique. A special type of opal is called a fire opal, as it displays a red hue with orange and yellow undertones. The rarest and most valuable types of opals are black opals.

Physical Properties of Tourmaline

Since tourmalines are easily confused with other gemstones, it’s important to know which distinctive physical properties they have. Even though tourmalines belong to the most complex group of silicate minerals, in terms of chemical composition, what sets them apart from other gemstones is their triagonal crystal structure. In other words, they contain three-sided or six-sided prisms with rounded edges. 

As mentioned before, tourmalines can occur in almost every color. While black opals are the rarest, black tourmalines are the most common. They’re otherwise known as schorl, and they are rich in iron. Pink and red tourmalines are also widely available, and they’re otherwise known as rubellites. A special type of tourmaline is called watermelon tourmaline. Due to the multicolor zoning that occurs within the mineral, these types of tourmalines have a pink core, surrounded by a green outer layer. 

What also makes tourmalines special is that they can be electrically charged when extreme heat or pressure is applied to them. Some types of tourmalines, mainly those that are opaque black, and yellow, have high magnetic susceptibilities. 

October Birthstones in Jewelry 

October Birthstones Jewelry infographic with images of opal and tourmaline rings

Opals have been worn in jewelry for thousands of years. The earliest opal artifacts ever found date back to 4000 BC, and they’re believed to come from Kenya. Even to this day, they are very popular because of their intricate patterns. People love wearing opal jewelry because no two opals are the same, making each piece of jewelry completely unique. 

Precious opals are often worn as rings, brooches, earrings, and necklaces. The bigger the stone, the better its play-of-color. They’re usually cut in a way to maximize the color-changing pattern, even if it makes the opal disproportional. Opals that have a dome-shaped surface are also the best cut for the play-of-color. Depending on their colors, opals can be paired with both silver and yellow gold. 

When it comes to tourmalines, it’s all about the intensity of the color. Red and pink tourmalines, as well as Paraiba tourmalines, are the most popular choices for jewelry. Paraiba tourmalines usually have a custom cut, due to their color pattern and high value. Common cuts for tourmalines include pear, oval, and brilliant cuts. They can also be fashioned into long rectangles. Due to its diversity, tourmalines can be worn as rings, necklaces, pendants, brooches, earrings, and bracelets. 

Price and Value of Opal and Tourmaline 

Price and Value of Opal and Tourmaline infographic with images of rings

Many factors can determine the price of these October birthstones. High-quality precious opals are sometimes more expensive than emeralds, sapphires, rubies, and even diamonds. An opal’s quality depends on three chief aspects: color, pattern, and clarity. It goes without saying that opals that have the play-of-color phenomenon are more valuable than common ones. 

White opals’ price normally varies from $20 to $200, while black opals can cost from $30 to $1,500 per carat. Black opals that have more carat weight, ranging from 5 to 10 carats, can cost as much as $50,000. Similarly, fire opals can cost $50 to $10,000 per carat. 

Tourmalines are more affordable than opals. For a standard tourmaline that has a generally good quality, one carat can cost from $50 to $750, depending on the color intensity and clarity. Rubellites, on the other hand, command a higher price, between $400 to $1,000 per carat. Paraiba tourmalines are the most valuable, and they can cost around $5,000 per carat. 

As with all colored gemstones, the more saturated their color, the more valuable the tourmaline is. Another factor that contributes to the price of tourmalines is the size. Paraiba tourmalines rarely come in more than 2 carats, so naturally, larger stones cost more. 

What Are the Most Expensive Types of Opal and Tourmalines?

Most Expensive Types of Opal and Tourmalines infographic with image of ring
A beautiful Tourmaline and Diamond Ring from our Collection

Although opals can be found in a variety of colors, the most valuable types of opals are black opals, specifically Australian black opals. They tend to have a black body color and lighter hues that are refracted against the light. Due to their rarity and their intense dark hues, they can cost from $10,000 to $50,000 per carat. Another reason why they’re so pricy is that they’re incredibly challenging to dig out. 

The most expensive types of tourmalines are the Paraiba tourmalines, which come from Brazil. They appear in blue, turquoise, and green colors. Even though they tend to contain abundant inclusions, they are the most valuable and also the rarest. Paraiba tourmalines with saturated, vivid colors can cost from $2,000 to $5,000 per carat. 

Similarly, colored tourmalines from Mozambique and Nigeria are also sometimes called Paraiba tourmalines since it’s so hard to tell them apart. That’s why you should always ask for a certificate distributed by a gemological laboratory. 

Shopping Tips for the October Opal Birthstone 

infographic of October opal shopping tips and opal engagement ring image

When shopping for the perfect opal, there are a few things you need to consider. If you’re in the market for a precious opal, then you can expect extravagant play-of-color. One opal can have five or six colors at once, and they change once you look at the opal from a different angle. If you’re looking for a single-colored gemstone with no secondary hues, then this might not be the right choice for you. Every opal is unique, and it can make a great replacement for a diamond engagement ring. 

The quality of an opal mainly depends on three factors: the opal’s color, pattern, and clarity. To fully evaluate an opal stone, you need to look at its color intensity and the quality of the play of colors. To do this, it’s best to place it against a light or dark background, depending on the opal’s color. Either way, you will want to make a sharp color contrast. 

Look at the opal’s transparency and clarity, and whether it’s opaque or not. Once again, this depends on the color. White and crystal opals should be transparent to some degree or entirely transparent. On the other hand, black opals are more valued when they’re opaque. 

If you want to buy any kind of gemstone, especially for an engagement ring, it’s important to ask for a certificate to prove its authenticity. The certificate should come from a reputable gemological institution. This can be a GIA, AGTA, AGL, or SSEF certificate. 

Shopping Tips for the October Tourmaline Birthstone 

infographic of October tourmaline shopping tips and tourmaline engagement ring image

There are many factors you need to think about when you’re shopping for a tourmaline birthstone. Its price will mainly depend on the color, clarity, and size of the tourmaline. The most expensive tourmaline birthstones are red, pink, blue, and green tourmalines. While black tourmalines are the most common, they’re also the least valuable. The reason for this is that they can absorb light, making them seem entirely opaque. 

Tourmalines are less expensive than some popular precious stones, and they can be great replacements for emeralds, rubies, sapphires, and even colored diamonds. Since tourmalines are made in hydrothermal environments, it’s normal for the liquid to be trapped in their minute inclusions. Depending on their color, they will easily join with a variety of settings, such as silver, platinum, yellow gold, white gold, and rose gold. 

If you want to get a Paraiba tourmaline birthstone, don’t forget to ask for an authenticity certificate from a gemological institute. These types of certificates prove the origin of the tourmaline, whether it has enhancements or treatments, and if it’s even real or synthetic. 

Cleaning Opal and Tourmaline Jewelry 

Cleaning opal and tourmaline jewelry graphic with tourmaline and opal ring images

Opals are among one of the most delicate gemstones. Treat them with extreme care. They are sensitive to sunlight and changes in temperature.

Since they are very easy to fracture, it’s best to remove them from precarious situations. If you want to wash them, use lukewarm water and a very small amount of soap. Don’t expose them to any chemicals and ultrasonic cleaners. If their surface scratches, they might lose a lot of their play-of-color. 

As for tourmalines, they’re much stronger and more durable than opals. While they’re harder to scratch or chip, they attract a lot of dust due to their electrical conductivity. Even though this means you’ll have to clean them more often, all you need is warm water and soap. Just like for opals, don’t use ultrasonic or steam devices to clean your tourmaline. If you expose your tourmaline to a sudden change in temperature, this can significantly damage it.

October Birthstones – Contact Us 

talk to a jewelry expert graphic with jeweler helping a happy customer

What both birthstones have in common is that they can display almost any color out there. Whether it’s one intense hue or a kaleidoscope of colors, opals, and tourmalines are unique and breathtaking gemstones that would enrich any jewelry collection. 

Do you have any questions about October birthstones? Do you want to shop for opal and tourmaline jewelry? Feel free to contact our jewelry experts.

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About Benjamin Khordipour

Benjamin Khordipour is one of the jewelry researchers and gemologists at Estate Diamond Jewelry. He received his official gemological degrees from both the GIA and GUBELIN. He also regularly contributes to Business Insider, Forbes, Rapaport, CNBC, and Brides Magazine. Benjamin was born in New York and joined Estate Diamond Jewelry in 2014. He is passionate about vintage jewelry and diamonds. This blog was built on his strong belief that jewelers have a responsibility to properly educate their customers. In 2019, Benjamin co-authored the book The Engagement Ring Guide for Men. His favorite vintage jewelry era is the Art Deco Era and his favorite type of stone is the Kashmir Sapphire. He also collects rare antique pins.