Spinel: A Gemstone of Enduring Beauty and Value

Spinel, often overlooked in favor of its more famous look-alikes like ruby and sapphire, is a captivating gemstone with a rich history and remarkable properties. Available in a stunning spectrum of colors and possessing excellent durability, spinel offers a compelling alternative for jewelry enthusiasts seeking both beauty and value.

Definition

Spinel is a naturally occurring mineral belonging to the oxide class of minerals. Chemically, it is magnesium aluminum oxide, with the formula MgAl2O4. While pure spinel is colorless, trace amounts of other elements can impart a wide range of vibrant colors, making it a versatile gemstone for jewelry design.

Key Features

Spinel stands out in the world of gemstones due to several key characteristics:

• Color Variety: Unlike many gemstones that are limited to a few hues, spinel boasts an impressive color palette. It can be found in fiery reds, brilliant pinks, vivid blues, deep purples, fiery oranges, and even black. The most sought-after are the vibrant reds (often called ‘Balas Ruby’ historically) and the intense cobalt blues.
• Exceptional Clarity: Spinel often exhibits excellent clarity, meaning it has fewer internal inclusions than many other gemstones. This contributes to its brilliance and sparkle.
• High Refractive Index: Spinel has a high refractive index, which gives it a desirable brilliance and fire.
• Hardness and Durability: With a Mohs hardness of 8, spinel is a very hard and durable gemstone, second only to diamond, sapphire, and ruby among common gemstones. This makes it well-suited for everyday wear in rings, pendants, earrings, and bracelets.
• No Enhancements: Most spinel on the market is natural and unenhanced. Unlike many other colored gemstones, spinel rarely undergoes treatments to improve its color or clarity. This natural state is a significant selling point for many buyers.

Origin and History

Spinel has a long and complex history, often intertwined with that of rubies. For centuries, many famous red gemstones were misidentified as rubies, when in fact, they were spinel. This confusion arose because both minerals often occur in the same geological environments and share similar physical properties, including a comparable hardness and crystal structure.

Historically significant deposits have been found in Sri Lanka, Myanmar (Burma), and Afghanistan. Tajikistan, Vietnam, and Madagascar are also important sources. The famed Mogok region in Myanmar has yielded some of the finest red and pink spinels.

Notable historical examples of spinel include the Black Prince's Ruby and the Timur Ruby, both part of the British Crown Jewels. These large, magnificent red stones, which were once believed to be rubies, are now recognized as exceptional spinel crystals.

Types / Variations

Spinel is primarily distinguished by its color, with specific hues often carrying historical or trade names:

• Red Spinel: Often referred to historically as ‘Balas Ruby’, these range from pinkish-red to deep, vibrant red.
• Pink Spinel: From delicate pastel shades to intense fuchsia.
• Blue Spinel: Can range from sky blue to deep, rich sapphire-blue, particularly those colored by cobalt.
• Purple Spinel: From lavender to deep amethyst-like shades.
• Orange Spinel: Including fiery shades and peachy tones.
• Black Spinel: Opaque and often used for its metallic luster, frequently cut into cabochons or beads.
• Colorless Spinel: Pure MgAl2O4, less common but can be mistaken for diamond.
• Pleochroic Spinel: Some spinels display different colors when viewed from different angles.

How It's Made

Spinel is a natural mineral formed deep within the Earth's mantle under conditions of high temperature and pressure. It typically forms in metamorphic rocks, such as marble and crystalline limestone, or in alluvial deposits derived from these rocks. The vibrant colors are due to the presence of trace elements:

• Red and pink colors are usually caused by chromium.
• Blue colors are often due to cobalt and sometimes iron.
• Violet hues can result from a combination of chromium and iron, or iron and cobalt.

Natural spinel is mined from deposits around the world. After extraction, rough spinel crystals are cleaned, sorted, and then cut and polished by lapidaries to bring out their best color, clarity, and brilliance. The cutting process is crucial in maximizing the gemstone's beauty and value.

Grading & Quality Standards

While there isn't a universally standardized grading system like the 4 Cs for diamonds, several factors determine the quality and value of spinel:

• Color: This is the most important factor. Vivid, saturated colors command the highest prices. For reds, a pure, vibrant red is ideal. For blues, a rich, intense cobalt blue is highly prized.
• Clarity: Like most gemstones, eye-clean spinel with minimal visible inclusions is preferred. However, some inclusions are natural and acceptable if they don't detract from the stone's beauty.
• Cut: A well-cut spinel will maximize its brilliance, fire, and color saturation. Poor cuts can make a stone appear dull or unevenly colored.
• Carat Weight: Larger spinels, especially in desirable colors, are rarer and thus more valuable per carat.

Reputable gemological laboratories, such as GIA, offer identification and origin reports for spinel, which can provide valuable information about the stone’s characteristics.

Buying Guide

When purchasing spinel, consider the following:

• Color: Decide which color appeals to you most. Remember that the intensity and purity of the color are key value drivers.
• Source: While spinel is found globally, certain origins are known for producing exceptional quality. For instance, Myanmar and Sri Lanka are famed for vibrant reds and pinks, while Vietnam and Sri Lanka can produce fine blues.
• Clarity: Look for stones that appear clean to the naked eye. Hold the stone face-up under good light and examine it from about 10-12 inches away.
• Cut: Ensure the cut is symmetrical and well-proportioned, allowing light to reflect evenly, creating sparkle and depth of color.
• Certification: For significant purchases, consider requesting a gemological report from a reputable laboratory that details the stone's characteristics and confirms its natural origin.
• Price: Compare prices from different reputable dealers. Because spinel is often unenhanced and more affordable than comparable sapphires or rubies, it offers excellent value.

Price Range & Value Factors

Spinel offers remarkable value for its beauty and durability. Prices vary widely depending on color, size, clarity, and cut. Generally, spinel is more affordable than rubies or sapphires of comparable quality.

• Color: The most significant factor. Vibrant red, intense pink, and deep cobalt blue spinels command the highest prices.
• Saturation and Tone: Highly saturated colors with an ideal tone (not too dark, not too light) are most valuable.
• Clarity: Eye-clean stones are more valuable.
• Cut: Fine cutting enhances brilliance and color, adding to value.
• Origin: Historically significant origins can sometimes add a premium, but color and quality are paramount.
• Rarity: Large, fine-quality spinels are rarer and thus command higher prices per carat.

Compared to rubies and sapphires, spinel can be significantly less expensive, often offering a more vivid color or better clarity for the same price point. This makes it an attractive choice for engagement rings or other statement jewelry.

Care and Maintenance

Spinel’s hardness (8 on the Mohs scale) makes it relatively easy to care for, but like all gemstones, it requires some attention to maintain its luster and integrity.

• Cleaning: Clean your spinel jewelry with warm water, mild soap (like dish soap), and a soft brush. Gently scrub the gemstone and the metal setting, then rinse thoroughly and dry with a soft, lint-free cloth.
• Avoid Harsh Chemicals: Do not expose spinel to ultrasonic cleaners, steam cleaners, or harsh household chemicals (like bleach or ammonia), as these can damage the stone or the setting.
• Storage: Store your spinel jewelry separately from other pieces to prevent scratching. A soft pouch or a lined jewelry box is ideal.
• Protection: While durable, it’s wise to remove spinel jewelry during strenuous activities, such as sports, gardening, or heavy cleaning, to avoid potential impacts or abrasion.

Pros and Cons

Pros:

• Beautiful and Diverse Colors: Offers a wide range of stunning hues.
• Excellent Durability: Hardness of 8 makes it suitable for daily wear.
• Often Unenhanced: Many spinels are natural and untreated, appealing to buyers seeking authenticity.
• Great Value: Offers comparable beauty and durability to more expensive gems like rubies and sapphires at a lower price point.
• Brilliance and Fire: High refractive index provides excellent sparkle.

Cons:

• Less Recognition: Not as widely known or sought after as some other colored gemstones, which can affect resale value in some markets.
• Historical Misidentification: Its history of being mistaken for ruby can sometimes lead to confusion.
• Rarity in Top Quality: While available, finding top-quality, large, unenhanced spinels in the most desirable colors can still be challenging.

Famous Examples

Several historically significant gemstones, once believed to be rubies, are now identified as fine examples of red spinel:

• The Black Prince's Ruby: A large, irregular, uncut red stone set in the Imperial State Crown of Great Britain. It is approximately 170 carats and is a vivid red color.
• The Timur Ruby: Another famous red stone from the British Crown Jewels, weighing about 352 carats. It features an engraved inscription and is a striking red color.
• The Samarian Spinel: A large, pale pink spinel reportedly weighing over 100 carats, historically owned by Mughal emperors.

These examples highlight the historical importance and impressive quality that spinel can achieve.

Common Misconceptions

• Spinel is a ruby or sapphire imitation: This is a common misconception due to historical misidentification. While they share similarities, spinel is a distinct mineral species with its own unique properties and value.
• All red gemstones are rubies: As demonstrated by famous examples, not all red gemstones are rubies. Red spinel has been highly prized for centuries.
• Spinel is not valuable: While generally more affordable than rubies or sapphires, high-quality spinel, especially in rare colors like vibrant red or cobalt blue, can be very valuable and command significant prices.

Related Terms

• Gemstone
• Mineral
• Oxide
• Corundum (the mineral family of ruby and sapphire)
• Mohs Hardness Scale
• Inclusions
• Clarity
• Color Saturation
• Balas Ruby (historical term for red spinel)
• Magnesium Aluminum Oxide

FAQs

What is spinel made of?

Spinel is chemically magnesium aluminum oxide (MgAl2O4). Its color comes from trace elements like chromium, iron, and cobalt.

Is spinel a hard gemstone?

Yes, spinel has a Mohs hardness of 8, making it very durable and suitable for everyday jewelry.

Is spinel treated?

Most spinel on the market is natural and unenhanced. Treatments are rare compared to other colored gemstones.

Which color of spinel is the most valuable?

Vibrant red, intense pink, and vivid cobalt blue spinels are generally the most valuable and sought-after colors.

Can spinel be used for engagement rings?

Absolutely. Its durability, beauty, and often unenhanced nature make it an excellent and often more affordable alternative to diamonds, sapphires, or rubies for engagement rings.

How does spinel compare to ruby and sapphire?

Spinel is as hard and durable as ruby and sapphire (both being 9 on the Mohs scale, with spinel at 8). It often offers a wider color range and can be significantly more affordable while maintaining excellent brilliance and clarity. Historically, fine red spinels were often mistaken for rubies.