Ruby: The King of Gemstones

Revered throughout history as the 'King of Gemstones,' the ruby commands attention with its vibrant red hue, symbolizing passion, protection, and prosperity. This magnificent gem has adorned royalty, been steeped in ancient lore, and continues to be one of the most sought-after precious stones in the world. Its fiery brilliance and exceptional durability make it a timeless choice for fine jewelry and a testament to nature's artistry.

Definition

A ruby is a precious gemstone, a variety of the mineral corundum, which also includes sapphire. What distinguishes a ruby from a sapphire is its color: rubies are exclusively red. This intense red coloration is primarily due to the presence of chromium within the crystal structure. Corundum, in its purest form, is colorless. However, trace elements infiltrate the crystal lattice during formation, creating the vast spectrum of colors seen in sapphires and the singular, captivating red of the ruby. With a hardness of 9 on the Mohs scale, rubies are second only to diamonds in durability, making them highly resistant to scratching and ideal for everyday wear.

Key Features

• Color: The most critical factor in a ruby's value, ranging from orangey-red to purplish-red. The most prized color is a pure, vivid red, often referred to as 'Pigeon's Blood.' This term describes a rich red with a slight purplish-red secondary hue, typically found in Burmese rubies. The intensity and saturation of the red are paramount.
• Hardness: Rating 9 on the Mohs scale of mineral hardness, rubies possess excellent durability, making them suitable for all types of jewelry.
• Luster: Rubies exhibit a vitreous (glass-like) luster, giving them a brilliant, reflective surface when polished.
• Clarity: Like most colored gemstones, rubies typically contain inclusions. Unlike diamonds, some inclusions, such as fine, silky rutile needles (known as 'silk'), can actually enhance a ruby's beauty by diffusing light and contributing to a soft, glowing appearance. However, large or prominent inclusions that detract from transparency or durability will lower the value.
• Pleochroism: Rubies are dichroic, meaning they can display different colors when viewed from different angles. Typically, a ruby will show a purplish-red and an orangey-red hue.
• Fluorescence: Many rubies, especially those from Myanmar (Burma), exhibit strong fluorescence under ultraviolet light. This internal glow can make the ruby appear more vivid and brilliant, even in dim lighting, and is a desirable characteristic.

Origin and History

Rubies have been cherished for millennia, with their earliest historical mentions tracing back over 2,500 years to ancient Sanskrit writings, where they were called 'ratnaraj,' meaning 'king of precious stones.' Ancient cultures believed rubies possessed mystical powers, offering protection, wealth, and good fortune to their wearers. Warriors carried them into battle for invincibility, and kings wore them as talismans of power and wisdom.

Historically, the Mogok Valley in Myanmar (Burma) has been the primary source of the world's finest rubies, renowned for their exceptional 'Pigeon's Blood' color. Other significant historical sources include Sri Lanka (Ceylon), Thailand, and Cambodia. In more recent times, major deposits have been discovered in Mozambique and Tanzania, which have become crucial suppliers to the global market. Rubies are typically found in metamorphic rocks like marble or basalt, formed under intense heat and pressure deep within the Earth's crust.

Types / Variations

While all rubies share the defining characteristic of being red corundum, variations primarily stem from their origin, which often influences their characteristic color and inclusions, and special optical phenomena:

• Burmese Rubies: Historically, the most famous and highly prized for their vivid 'Pigeon's Blood' red color and often strong fluorescence. They frequently contain fine rutile silk.
• Thai Rubies: Tend to be a darker, more brownish-red due to higher iron content, and generally exhibit less fluorescence.
• African Rubies: Rubies from Mozambique and Tanzania often display vibrant reds similar to Burmese stones, and have become significant in the market.
• Star Rubies: A rare and captivating variety that exhibits asterism, a star-like phenomenon caused by reflections from precisely aligned rutile needles (silk) within the stone. When cut en cabochon (a smooth, rounded shape), a six-rayed star appears to float across the gem's surface.

How It's Made

Natural Formation

Natural rubies form in metamorphic or igneous rocks. In metamorphic environments, such as marble or gneiss, extreme heat and pressure cause aluminum-rich minerals to recrystallize. If chromium is present as a trace element, it substitutes for aluminum in the crystal lattice, leading to the distinctive red color. In igneous environments, rubies can form in basaltic rocks, typically in areas with volcanic activity.

Synthetic Rubies

Synthetic rubies have been produced since the late 19th century and are chemically, physically, and optically identical to natural rubies, differing only in their origin. Common methods include:

• Verneuil (Flame Fusion): The earliest and most cost-effective method. Aluminum oxide powder is dropped through a flame, melting and solidifying into a single crystal.
• Czochralski (Crystal Pulling): A seed crystal is slowly pulled from a crucible of molten corundum, forming a large crystal. This method produces high-quality material.
• Flux Growth: Rubies grow slowly from a molten flux solution, mimicking natural conditions more closely. This method can produce synthetic rubies with inclusions similar to natural ones, making identification more challenging.
• Hydrothermal Growth: Crystals are grown in a high-pressure, high-temperature aqueous solution, closely replicating natural formation.

Distinguishing natural from synthetic rubies typically requires specialized gemological equipment to identify subtle differences in growth patterns, inclusions, and trace elements.

Grading & Quality Standards

Ruby quality is evaluated using the 'Four Cs,' similar to diamonds, but with a significant emphasis on color:

• Color

  This is the most crucial factor. A ruby's color is assessed based on three components: hue (the pure red color, often with secondary tints of orange or purple), tone (lightness or darkness), and saturation (intensity or vividness). The ideal is a pure, intense, vivid red with medium-dark tone, often referred to as 'Pigeon's Blood.'

• Clarity

  Rubies are rarely 'eye-clean' (free of inclusions visible to the naked eye). Minor inclusions are accepted and can even indicate natural origin. The value decreases if inclusions are prominent, diminish transparency, or affect durability. 'Silk' (rutile needles) is a common and often desirable inclusion.

• Cut

  The cut of a ruby refers to its proportions, symmetry, and polish. A well-cut ruby maximizes its color, brilliance, and scintillation (sparkle). Common cuts include oval, cushion, round, and emerald cuts. The cutter aims to preserve carat weight while enhancing the gem's inherent beauty.

• Carat Weight

  Rubies are weighed in carats (1 carat = 0.2 grams). Larger rubies are exceedingly rare and, therefore, command significantly higher prices per carat, especially when coupled with high color and clarity.

• Treatments

  A significant portion of rubies on the market are treated to improve their color or clarity. Disclosure of treatments is paramount:

  • Heat Treatment: The most common and accepted treatment. It involves heating the ruby to high temperatures to improve color and clarity. It is generally stable and permanent.
  • Fracture Filling: Involves filling surface-reaching fractures with lead glass or other substances to improve clarity and appearance. This treatment is less stable and requires careful handling.
  • Beryllium Diffusion: A high-temperature treatment where beryllium is introduced to alter the ruby's color.
  • Dyeing: Less common for fine rubies, but low-quality material may be dyed to enhance color.

• Certification

  For significant ruby purchases, a reputable gemological laboratory report (e.g., GIA, AGL, Gübelin) is highly recommended. These reports confirm the gem's identity, natural or synthetic origin, treatments, and provide a detailed analysis of its quality characteristics.

Buying Guide

Purchasing a ruby is a significant investment, and careful consideration is key:

• Prioritize Color: Always prioritize the ruby's color above other factors. Seek a vibrant, intense red that appeals to you.
• Understand Treatments: Inquire about any treatments the ruby has undergone. Heat treatment is common and accepted, but treatments like fracture filling or dyeing significantly impact value and durability. Ensure full disclosure from the seller.
• Examine Clarity: While some inclusions are normal, avoid stones with large, eye-visible inclusions that detract from beauty or compromise durability.
• Check Certification: For high-value rubies, insist on a certificate from an independent and reputable gemological laboratory.
• Consider the Setting: The metal and design of the jewelry should complement the ruby's beauty. Gold (yellow or white) and platinum are popular choices.
• Reputable Jeweler: Buy from a trustworthy jeweler with a strong reputation and clear return policies.

Price Range & Value Factors

The price of a ruby can vary dramatically, ranging from hundreds to millions of dollars per carat. Several factors contribute to its value:

• Color: The most dominant factor. 'Pigeon's Blood' rubies from historic sources command the highest prices. Pure, vivid red with strong saturation is always more valuable.
• Clarity: Eye-clean stones are more valuable, though minor, non-detracting inclusions are acceptable.
• Carat Weight: As with most gemstones, price per carat increases exponentially with size. Large, high-quality rubies are exceedingly rare.
• Origin: Rubies from historically significant mines like Mogok (Burma) or new prime sources like Mozambique can fetch premium prices, especially if certified.
• Treatment: Untreated rubies of fine quality are significantly more valuable than treated ones. Heat-treated rubies are generally more valuable than those with fracture filling or diffusion.

Care and Maintenance

Thanks to its excellent hardness, a ruby is a durable gemstone suitable for everyday wear, but proper care is still essential:

• Cleaning: The safest way to clean ruby jewelry is with warm, soapy water and a soft brush.
• Ultrasonic and Steam Cleaners: Generally safe for untreated or heat-treated rubies. However, avoid these methods for rubies that have been fracture-filled or dyed, as the treatments can be damaged. Always confirm the treatment type before using mechanical cleaners.
• Storage: Store ruby jewelry separately from other pieces to prevent scratching, as it can scratch softer gems and metals.
• Chemicals: Avoid exposure to harsh chemicals, strong acids, and extreme temperature changes, which can damage treatments or, in rare cases, the stone itself.
• Impact: While hard, rubies are not indestructible. Protect them from sharp blows that could cause chipping or fracturing.

Pros and Cons

Pros:

• Exceptional Durability: With a Mohs hardness of 9, rubies are highly resistant to scratching, making them excellent for daily wear.
• Stunning Beauty: Their intense red color is captivating and universally adored.
• Historical Significance: Rich in lore and symbolism, rubies carry a sense of heritage and prestige.
• Investment Potential: High-quality, untreated rubies, particularly those from prized origins, can be excellent investments.
• Versatility: Suitable for all types of jewelry, from rings and necklaces to earrings and bracelets.

Cons:

• High Price: Fine rubies are among the most expensive gemstones, especially in larger sizes.
• Common Treatments: Many rubies on the market are treated, and some treatments (like fracture filling) can affect durability and require specific care.
• Clarity Issues: It's rare to find an eye-clean ruby, and some inclusions can detract from its beauty.
• Color Variability: The range of red can vary significantly, and less desirable brownish or purplish tints are common.

Famous Examples

• The Sunrise Ruby: A 25.59-carat 'Pigeon's Blood' Burmese ruby, set between two shield-shaped diamonds and mounted on a ring by Cartier. It sold for a record-breaking $30.3 million in 2015, making it the most expensive ruby ever sold at auction.
• The Graff Ruby: A magnificent 8.62-carat 'Pigeon's Blood' ruby that sold for $8.6 million in 2014, known for its exceptional color and rarity.
• The Carmen Lúcia Ruby: A 23.1-carat Burmese ruby, considered one of the finest and largest faceted Burmese rubies in the world. It is part of the National Gem and Collection at the Smithsonian National Museum of Natural History.
• The De Long Star Ruby: A 100.32-carat star ruby, notable for its distinct six-rayed star. It was famously stolen and later recovered, now residing in the American Museum of Natural History.

Common Misconceptions

• All red gemstones are rubies: Many other red stones exist, such as garnets, spinels, tourmalines, and topazes. Only red corundum is a ruby.
• All inclusions are bad: While large, detracting inclusions lower value, fine rutile 'silk' can enhance a ruby's beauty (creating a soft glow or asterism) and confirm its natural origin.
• Heat treatment is always bad: Heat treatment is a stable and widely accepted enhancement for rubies. While untreated rubies are more valuable, heat-treated ones offer excellent beauty at a more accessible price point. The key is full disclosure.
• Synthetic rubies are not 'real' gemstones: Synthetic rubies are chemically, physically, and optically identical to natural ones, just grown in a lab. They are 'real' rubies, but their origin affects their value significantly.

Related Terms

• Corundum: The mineral family to which ruby and sapphire belong.
• Sapphire: Any color of corundum other than red.
• Chromium: The trace element responsible for the ruby's red color.
• Pigeon's Blood: The most prized, vivid red color for a ruby, with a slight purplish-red tint.
• Star Ruby: A ruby exhibiting asterism (a star-like effect).
• Burma Ruby: A ruby from Myanmar, historically considered the finest.
• Heat Treatment: A common and accepted enhancement process for rubies.
• Fluorescence: The ability of some rubies to glow under ultraviolet light.
• Inclusions: Internal characteristics within a gemstone.
• Mohs Hardness Scale: A scale measuring a mineral's resistance to scratching.

FAQs

1. What is the most valuable color for a ruby?

   The most valuable color is a pure, vivid, intense red, often called 'Pigeon's Blood,' with strong saturation and medium-dark tone.

2. Are rubies rare?

   High-quality, large, natural rubies with excellent color and minimal treatments are exceptionally rare, making them highly valuable.

3. Can rubies be faked?

   Yes, rubies can be imitated by other red stones or created synthetically. Always buy from a reputable jeweler and request gemological certification for significant purchases.

4. What's the difference between a ruby and a red sapphire?

   There is no such thing as a 'red sapphire.' By definition, if the corundum is red, it is a ruby. All other colors of corundum are sapphires.

5. Are synthetic rubies real?

   Synthetic rubies are chemically, physically, and optically the same as natural rubies, so in that sense, they are 'real' rubies. However, they are created in a laboratory, which significantly impacts their value compared to natural stones.