Your Complete Guide to Opal Clarity

By: WC Editorial Team Read Time: 3 mins Gemstone Insights

May 31, 2023

Are you interested in investing in opal jewelry but are unsure about how to get the most bang for your buck? If so, try not to get overwhelmed–we’ve all been there. With such a massive jewelry market full of everything from opal earrings and opal rings for women to the classic opal necklace and opal bracelet, it can be understandably challenging to make a smart and confident decision. After all, where do you even start? The answer is a lot simpler than you probably think. So, what is the opal stone meaning? The October birthstone opal is widely known to symbolize fidelity and confidence and is often used in vintage-style jewelry. Interested in learning more? If so, this guide covers everything you need to know about opal clarity. From gemstone clarity and the opal clarity scale to opal inclusions and value, we’ll help you understand what you need to know when shopping for the classic opal stone.

Gemstone Clarity Clarity and Opal Value Types of Opal Inclusions Bubbles Vegetation Matter Host Rock Potch Dendritic Opal Clarity Scale

Gemstone Clarity

Gemstone clarity is one of four major Cs of gemstone grading. The grade a stone is assigned represents the relative absence of inclusions or materials trapped within the gem, blemishes, fractures, and other imperfections that affect its integrity. The other three Cs include color, cut, and carat weight. Together, these classifications help to determine a gemstone’s overall value.

Clarity and Opal Value

An opal stone’s clarity is a description of its level of transparency and the presence of any visible inclusions, which we’ll discuss in detail later. An opal stone’s clarity can range from completely transparent to opaque, with each providing the best background for displaying an array of unique colors that are synonymous with the opal. As you can likely imagine opals that present a milky or cloudy background is less valuable as it makes the stone unappealing and potentially unstable. Many factors play into an opal’s clarity assessment, including the presence of pits, fractures, or fragments of its host rock, also known as a Matrix. Another factor is whether to stone has undergone crazing or a loss of moisture as it can cause a series of cracks similar to a spider web.

Types of Opal Inclusions

As we mentioned in one of the prior sections, many different opal inclusions can exist. We’ll discuss that in more detail below–check it out.

Bubbles

Many gemstones including opals sometimes appear to contain bubbles, although, they are less rounded and more angular. Typically, these occur from two or three-phase inclusions and can contain either fluid and gas or fluid and a solid. Typically, these inclusions form when an opal forms rapidly, resulting in the trapping of other surrounding organic materials.

Vegetation Matter

As you can likely imagine, when an opal stone grows quickly as mentioned prior, it can also trap vegetation matter. More often than not, this includes plant roots and other vegetation found deep in the soil.

Host Rock

Some opals have been seen to contain fragments of their host rock, also known as a matrix. While not always the case, matrices in polished opals can be detrimental to their overall value and appearance. In the end, it depends on the variety of opal stones in question.

Potch

The opal stone is comprised of tiny silica spheres that, when perfectly aligned, give off a variety of colors. If they are random and misaligned, they are considered potch. Ultimately, this inclusion makes the stone a common opal and is therefore not typically high in value.

Dendritic

A dendritic inclusion resembles a heavily branches tree spreading up and around the opal. This occurs as a result of the presence of several fern-like inclusions, including iron, manganese, and other metallic oxides.

Opal Clarity Scale

Naturally, to grade an opal thoroughly and accurately, a comprehensive scale is used. Overall, there are four categories an opal can fall into based on its characteristics ranging from Good or (A) to Heirloom (AAAA). (A) is comprised of 75% of the world’s available opal stones which are milky and completely lacking in color. (AA) or Better includes the top 33% of available opals. They are milky and opaque in appearance with a low play of color. The Best (AAA) grade dictates those top 10% of opals that are milky with a medium play of color. Last and definitely not least, the Heirloom (AAAA) grade includes the top 1% of extraordinary opals that are both opaque and surface clean. Keep in mind, however, that the next time you’re shopping for an opal birthstone ring or opal wedding ring, you’re not likely to get your hands on an AAAA or AAA grade.

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FAQs

Which grade is ideal when shopping for opals?

There are five grades assigned to opals, ranging from below commercial and commercial to good, fine, and extra fine. Naturally, the fine and extra fine is the best grades, however, they are either difficult to get one’s hands on or considerably pricey.

How can you gauge the quality of an opal?

In terms of opal quality, there are three major aspects to consider. These include opal color, opal pattern, and opal clarity. An evaluation under controlled lighting against a dark background can ultimately determine these factors most effectively.

Do opals have visible inclusions?

In short, yes. No matter the variety of opals in question, the vast majority of opals have some sort of visible inclusions, whether it be spots or lines of potch.

Which opal type has the best clarity?

When it comes to the opal stone, there are several varieties, each with its level of preferable clarity. Black opals, for example, are prized by experts when they have a more opaque background. For crystal opals, a more transparent appearance is desired. In the end, it depends on your personal preference.