Value and Authenticity: Reza Piroznia’s Framework for Evaluating Lapis Lazuli Inclusions

I am Reza Piroznia, FCGmA—Master Artisan, Certified Gemmologist. Part of our Ultimate Lapis Lazuli Guide. The investment potential of lapis lazuli is influenced by multiple factors explored in depth in our Lapis Lazuli master guide that covers all essential aspects.

This technical guide will serve as a comprehensive exploration of Lapis Lazuli inclusions and their critical role in determining both its value and authenticity. Through my extensive experience, encompassing years at George Brown College and decades in my own workshop, I have developed a refined framework for analyzing these inclusions. This framework not only helps differentiate genuine Lapis Lazuli from imitations, but also provides a nuanced understanding of the factors that contribute to its overall quality and desirability.

The Enduring Allure of Lapis Lazuli

Lapis Lazuli, with its deep celestial blue hue and mesmerizing flecks of gold pyrite, has captivated humanity for millennia. From the tombs of ancient Egypt to the jewelry of Renaissance Europe, Lapis Lazuli has served as a symbol of royalty, power, and spiritual enlightenment. Its rich history and association with creativity and wisdom continue to fuel its popularity in the modern world.

But this popularity also comes with its own challenges. The allure of Lapis Lazuli, and its potential for substantial value, has unfortunately led to the proliferation of imitations and treatments designed to deceive unsuspecting buyers. Therefore, a thorough understanding of the stone's characteristics, particularly its inclusions, is crucial for making informed decisions.

Why Inclusions Matter: Unveiling the Story Within

Inclusions are inherent imperfections within a gemstone. Often viewed negatively in other stones like diamonds (where clarity is paramount), inclusions in Lapis Lazuli are not only acceptable but often desirable. They provide a fingerprint, a unique identifier that tells a story about the stone's origin, formation, and authenticity. They are, in essence, the key to unlocking the true value and nature of Lapis Lazuli.

My approach emphasizes a holistic understanding of these inclusions. We need to consider not just their presence or absence, but also their type, distribution, abundance, and how they interact with the overall color and texture of the stone. This multi-faceted approach allows us to differentiate between natural inclusions, which are a hallmark of genuine Lapis Lazuli, and artificial additions used in imitations or enhancements.

The FCGmA Standard and Lapis Lazuli Verification

As a Fellow of the Canadian Gemmological Association (FCGmA), I adhere to the highest standards of ethical and professional practice. The FCGmA designation signifies a commitment to accurate gem identification, objective grading, and transparent disclosure. This is especially important when dealing with Lapis Lazuli, where the potential for misrepresentation is significant.

The FCGmA standard emphasizes a combination of macroscopic observation (using the naked eye or a jeweler's loupe) and microscopic analysis (using a gemmological microscope). We employ a range of analytical techniques, including refractive index measurement, specific gravity determination, and spectroscopic analysis when necessary, to confirm the identity and authenticity of Lapis Lazuli specimens.

When evaluating Lapis Lazuli, the FCGmA framework particularly stresses the importance of carefully examining the following inclusion types, which I will elaborate on in detail:

• Pyrite (Iron Sulfide - $FeS_2$): The most common and often most valuable inclusion in Lapis Lazuli.
• Calcite (Calcium Carbonate - $CaCO_3$): Present in varying amounts and impacting the overall color.
• Sodalite (Sodium Aluminum Silicate Chloride - $Na_8Al_6Si_6O_{24}Cl_2$): Contributing to color variations within the stone.
• Other Minerals: Such as Diopside ($CaMgSi_2O_6$), Mica, and Hauyne ($Na_3Ca(Si_3Al_3)O_{12}(SO_4,Cl)(OH)_2$).
• Fractures and Veins: Naturally occurring cracks and fissures that can affect the stone's durability and appearance.

Common Inclusions and Their Significance: Pyrite and Calcite

Let's begin with two of the most frequently encountered inclusions in Lapis Lazuli: Pyrite and Calcite. Understanding these inclusions is fundamental to determining the authenticity and value of the stone.

Pyrite ($FeS_2$): The Golden Gleam

Pyrite, also known as "fool's gold," is a metallic, golden-yellow mineral that is almost always present in natural Lapis Lazuli. It is often dispersed as small, randomly distributed flecks throughout the blue matrix. The presence of pyrite is a strong indicator of authenticity, though its abundance and distribution significantly influence the stone's value.

Key Considerations for Pyrite Inclusions:

• Abundance: The amount of pyrite can vary widely. While some pyrite is generally desirable, excessive amounts can detract from the overall beauty of the Lapis Lazuli by diluting the intense blue color.
• Distribution: Evenly distributed, fine pyrite flecks are often considered more desirable than large, concentrated clusters. Uneven distribution can create unsightly patches and diminish the stone's aesthetic appeal.
• Form: Pyrite can occur as individual crystals, granular aggregates, or vein-like structures. Well-formed, sharply defined crystals are often more aesthetically pleasing than amorphous masses.
• Luster: The metallic luster of pyrite should be bright and reflective. Dull or tarnished pyrite may indicate alteration or weathering.

It is crucial to differentiate genuine pyrite inclusions from artificial imitations. Some fraudulent Lapis Lazuli specimens contain brass filings or other metallic materials added to mimic the appearance of pyrite. These artificial additions are often irregularly shaped, unevenly distributed, and lack the characteristic luster of natural pyrite. Microscopic examination is usually sufficient to distinguish between genuine and artificial pyrite inclusions.

Calcite ($CaCO_3$): The White Veil

Calcite is another common inclusion in Lapis Lazuli. It appears as white or light-colored streaks, patches, or veins within the blue matrix. Unlike pyrite, which generally enhances the value of Lapis Lazuli (within reasonable limits), calcite inclusions are typically considered less desirable. They can dilute the intense blue color and create an uneven, mottled appearance.

Key Considerations for Calcite Inclusions:

• Abundance: The amount of calcite is a crucial factor in determining the value of Lapis Lazuli. Stones with minimal calcite are generally more highly prized. Excessive calcite can significantly reduce the stone's value.
• Distribution: Calcite distributed as fine, hairline veins may be less objectionable than large, prominent patches. Uneven distribution can create unsightly blemishes and diminish the stone's aesthetic appeal.
• Color: The color of the calcite can vary from pure white to grayish or yellowish. Pure white calcite is generally considered less detrimental than discolored calcite.
• Transparency: Calcite is typically opaque, but it can occasionally exhibit some degree of translucency. The transparency of calcite does not typically affect the overall value of Lapis Lazuli.

It is essential to understand that some degree of calcite is often unavoidable in natural Lapis Lazuli. However, excessive calcite can compromise the stone's color and overall appearance. Treatments, such as dyeing, are sometimes used to mask or reduce the visibility of calcite inclusions. Therefore, a thorough examination is necessary to detect any signs of enhancement.

Looking Ahead

In the next part of this guide, we will delve deeper into the other types of inclusions commonly found in Lapis Lazuli, including Sodalite, other minerals, and fractures. We will also explore the methods used to detect and identify treatments designed to enhance the appearance of the stone. Remember, knowledge is your greatest asset when evaluating Lapis Lazuli. By understanding the significance of its inclusions, you can make informed decisions and appreciate the true beauty and value of this remarkable gemstone.

Value and Authenticity: Reza Piroznia’s Framework for Evaluating Lapis Lazuli Inclusions – Part 2

Welcome back, gem aficionados! In Part 1, we laid the groundwork for understanding the importance of inclusions in evaluating Lapis Lazuli, focusing on Pyrite and Calcite. Now, we’ll delve into other key inclusion types and explore the methods used to detect treatments, equipping you with the knowledge to make informed judgments about this captivating gemstone.

Expanding Our Inclusional Palette: Sodalite, Other Minerals, and Fractures

Beyond Pyrite and Calcite, Lapis Lazuli often features a range of other inclusions that contribute to its unique character. Understanding these inclusions is crucial for a comprehensive evaluation.

Sodalite ($Na_8Al_6Si_6O_{24}Cl_2$): The Blue Within the Blue

Sodalite is a member of the feldspathoid group and is, in fact, a key component of Lapis Lazuli, contributing to its characteristic blue color. While often considered an integral part of the Lapis matrix, larger concentrations of Sodalite can appear as distinct, slightly lighter or differently shaded blue areas within the stone.

Key Considerations for Sodalite Presence:

• Color Variation: Sodalite can cause variations in the blue color, ranging from a deep, intense blue to a slightly lighter, more grayish-blue. While a uniform, intense blue is generally prized, subtle variations due to Sodalite can add character and visual interest.
• Distribution: Similar to other inclusions, the distribution of Sodalite is important. Evenly distributed Sodalite, contributing to a consistent blue hue, is usually preferred. Concentrated patches can create a mottled appearance, which may be less desirable depending on the overall aesthetic.
• Identification: Distinguishing Sodalite from other blue minerals within Lapis Lazuli can be challenging without advanced gemmological testing. However, careful observation of color variations and texture can provide clues.

Other Minerals: A Geological Tapestry

Lapis Lazuli can contain a variety of other mineral inclusions, reflecting its complex geological formation. These inclusions, though often less prominent than Pyrite, Calcite, or Sodalite, can offer valuable insights into the stone's origin and authenticity. Some of the more commonly encountered minerals include:

• Diopside ($CaMgSi_2O_6$): A silicate mineral that can appear as small, greenish grains or crystals.
• Mica: A group of sheet silicate minerals that can create a shimmering or reflective effect within the stone.
• Hauyne ($Na_3Ca(Si_3Al_3)O_{12}(SO_4,Cl)(OH)_2$): Another member of the sodalite group, contributing to the blue color and potentially appearing as distinct inclusions.

The presence of these other minerals, while not always readily identifiable without microscopic analysis, can contribute to the overall complexity and beauty of Lapis Lazuli. They also serve as an important indicator of natural origin, as synthetic imitations rarely replicate this intricate mineral composition.

Fractures and Veins: Nature's Imperfections

Fractures and veins are naturally occurring cracks and fissures that can develop within Lapis Lazuli. These features can affect the stone's durability and appearance, and their presence requires careful consideration.

Key Considerations for Fractures and Veins:

• Extent and Severity: The size and number of fractures and veins are crucial factors. Extensive or deep fractures can weaken the stone and make it more susceptible to damage.
• Visibility: Prominent fractures and veins can detract from the stone's aesthetic appeal, especially if they are discolored or filled with foreign materials.
• Treatment: Fractures are often filled with resins or other substances to improve the stone's durability and appearance. Detecting these treatments is essential for accurate valuation.

While fractures are generally considered undesirable, fine, hairline veins can sometimes add character to the stone, particularly if they are filled with Pyrite or other visually appealing minerals. The overall impact of fractures and veins depends on their extent, visibility, and location within the stone.

Detecting Treatments and Enhancements: Unmasking the Artificial

Due to its value and desirability, Lapis Lazuli is often subjected to various treatments designed to enhance its appearance or mask imperfections. Identifying these treatments is crucial for making informed purchasing decisions. Some common treatments include:

• Dyeing: Used to intensify the blue color of Lapis Lazuli or to mask the presence of calcite inclusions. Dyeing can be detected by examining the stone under magnification for concentrations of dye in cracks and crevices. A cotton swab moistened with acetone can sometimes reveal dye residue.
• Waxing/Oiling: Used to improve the luster and surface appearance of the stone. Waxing and oiling can be detected by examining the stone under magnification for a greasy or waxy film.
• Resin Filling: Used to fill fractures and improve the stone's durability and appearance. Resin filling can be detected by examining the stone under magnification for a glassy or transparent substance filling cracks.
• Impregnation with Polymers: Similar to resin filling, this process uses polymers to fill pores and stabilize the stone. Detection methods are also similar to those for resin filling.
• Reconstitution: Lower quality Lapis Lazuli can be crushed and mixed with a binder (often plastic) to create a new stone. This is done to fabricate Lapis Lazuli cabochons and beads.

A combination of macroscopic and microscopic examination, along with other gemmological testing techniques, is often necessary to detect these treatments with certainty. Refractive index measurements and specific gravity determinations can also provide clues, though they may not always be conclusive.

'The Master's Bench' Table

Here's a handy reference table for Lapis Lazuli, providing key gemmological properties:

Property	Value
Refractive Index	Approximately 1.500 (varies slightly depending on composition)
Mohs Hardness	5 - 6
Specific Gravity	2.7 - 2.9

'Reza’s Authentication Tip'

When I examine Lapis Lazuli, the first thing I look for is the "sparkle" of genuine pyrite. It's not just about the presence of the gold flecks; it's about how they catch the light. Artificial imitations often use brass filings, which lack the sharp, metallic luster of natural pyrite. Also, I always smell the stone when doing a gemmological test. Natural Lapis Lazuli will have a 'sulphur' small when grinding for testing. However, be careful when doing this test as breathing in grinded gem particles is never good. - Reza Piroznia, FCGmA

A Holistic Approach to Evaluation

Ultimately, evaluating Lapis Lazuli is a holistic process that requires considering all of these factors in conjunction. The type, abundance, distribution, and interaction of inclusions, along with the stone's color, texture, and overall appearance, all contribute to its value and authenticity. A thorough understanding of gemmological principles, combined with practical experience, is essential for making informed judgments.

Conclusion

Lapis Lazuli, with its rich history and captivating beauty, remains a prized gemstone. By understanding the significance of its inclusions and the methods used to detect treatments, you can appreciate the true value and authenticity of this remarkable stone. Remember that this is just an overview. The world of gemmology is always growing as science allows us to develop as gemmologists. Always be open to learning more.

BIBLIOGRAPHY

1. Hurlbut, Cornelius S., and Klein, Cornelis. Manual of Mineralogy. 20th ed. New York: John Wiley and Sons, 1985.
2. Liddicoat, Richard T. Handbook of Gem Identification. 12th ed. Santa Monica, CA: Gemological Institute of America, 1989.
3. Nassau, Kurt. Gemstone Enhancement. 2nd ed. Boston: Butterworth-Heinemann, 1994.
4. Walton, Sir James. Physical Gemmology. New York: Sir Isaac Pitman & Sons LTD, 1952.
5. Reza Gem Collection Research Lab. Lapis Lazuli Inclusion Analysis. Unpublished Research Notes, 2023.

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