Ruby Properties and Characteristics

Last updated on July 3, 2023

Ruby is one of the four recognized precious gemstones, along with emerald, sapphire, and diamond. Being the birthstone of July, it has been admired as one of the highest-valued coloured gems since the beginning of recorded history.

Ruby Origin and Formation

Rubies are exquisite gemstones prized for their captivating red colour and exceptional beauty. The name “ruby” is derived from the Latin word “ruber” and its variant “rubeus,” both of which mean “red.” In the ancient Indian language of Sanskrit, rubies are referred to as “ratnaraj,” which translates to “king of precious stones.” This designation highlights the esteemed status and regal qualities attributed to rubies.

Interestingly, in ancient times, before the advancements in gemological knowledge and technology, all red gemstones were often considered rubies. This included gems like spinel, garnet, and tourmaline, which were not yet distinguished as separate varieties.

The formation of rubies is a fascinating process that begins in the Earth’s mantle, a layer located approximately 30 to 150 kilometres beneath the surface. In this region, intense heat and pressure create the perfect conditions for the formation of minerals. One such mineral is corundum, which consists of aluminum and oxygen atoms arranged in a crystal lattice structure.

Over millions of years, geological forces, such as volcanic activity and tectonic movements, can push the corundum crystals closer to the Earth’s surface. These crystals are often transported within molten rock called magma, which rises through cracks and fractures in the Earth’s crust. As the magma cools and solidifies, it forms igneous rocks. During this cooling process, the corundum crystals become trapped within igneous rocks, such as granite or basalt. This stage is crucial for the formation of rubies, as it provides the necessary conditions for the gem to develop its distinct characteristics.

As the magma cools, the corundum crystals undergo a process called crystallization. Atoms within the crystal structure rearrange themselves, and certain impurities or trace elements can find their way into the crystal lattice. One such trace element that significantly impacts the colour of rubies is chromium. The presence of chromium gives rubies their vibrant red hue. The presence of other elements, such as iron and titanium, can influence the colour and quality of rubies as well. For instance, a ruby with a higher iron content may exhibit a slightly darker shade of red.

The geographical origin of rubies also plays a role in their formation. Different regions around the world have unique geological conditions that contribute to the development of rubies with varying characteristics. For example, rubies from Myanmar (formerly Burma) are highly prized for their intense red colour and exceptional transparency.

In addition to Myanmar, rubies can be found in various other countries, including Afghanistan, Australia, Cambodia, China, Colombia, India, Kenya, Madagascar, Malawi, Mozambique, Nepal, Pakistan, Russia, Sri Lanka, Switzerland, Tajikistan, Tanzania, Thailand, the USA, Vietnam, and Zimbabwe. Each location offers its geological environment, which influences the quality, colour, and overall beauty of the rubies found there.

Ruby Colour

The colour of rubies is undoubtedly their most captivating and defining characteristic. The red colour of rubies is primarily attributed to the presence of chromium within the crystal lattice structure of corundum. When chromium replaces some of the aluminum atoms in the corundum structure, it imparts a deep red hue to the gemstone.

The range of red exhibited by rubies can vary from pinkish-red to a rich, deep red. The most prized and sought-after rubies possess a pure red hue, often referred to as “pigeon’s blood” red. These exceptionally rare rubies display a captivating, intense red colour with a slight hint of blue undertones.

The colour of rubies can be influenced by various factors, including the presence of other trace elements and the geological conditions in which they are formed. For instance, iron and titanium impurities can affect the shade and tone of the red colour, resulting in variations ranging from lighter pinkish-red to deeper, more saturated red hues.

The colour of rubies is highly valued, and gemologists use several criteria to assess and grade the quality of a ruby’s colour. These criteria include hue, tone, and saturation. The ideal hue for ruby is pure red without any noticeable undertones of orange or purple. The tone refers to the lightness or darkness of the colour, with medium to medium-dark tones being highly desirable. Saturation refers to the intensity or vividness of the colour, with well-saturated rubies commanding a higher value.

Ruby Clarity

Like other gemstones, rubies can have various types of inclusions. These inclusions are formed during the gem’s growth process deep within the Earth and can include tiny mineral crystals, needle-like rutile inclusions, and even fingerprint-like growth patterns. They are often the result of natural impurities or environmental conditions present during the gem’s formation.

Inclusions can affect the transparency and visual appearance of a ruby. The clarity of a ruby is determined by the size, type, number, and location of these inclusions. Rubies with fewer and less visible inclusions are considered to have higher clarity and are generally more valuable. However, it’s important to note that rubies are rarely found completely free of inclusions. In fact, the presence of certain types of inclusions can sometimes indicate a ruby’s authenticity and natural origin.

It is worth mentioning that certain types of inclusions can also contribute to the gem’s beauty and visual appeal. For instance, needle-like inclusions that intersect at precise angles within a ruby can create a phenomenon known as asterism, where the gem exhibits a star-like pattern when viewed under a focused light source. These rare “star rubies” with asterism can command high prices due to their uniqueness.

Ruby Cut

The cut of a ruby is a crucial factor in determining its visual impact and can greatly enhance or diminish the stone’s value.

A ruby’s crystal shape plays a significant role in determining its cut and proportions. As a result, the most common shapes available on the market are oval and cushion, featuring brilliant cut crowns and step cut pavilions. Other cuts, such as round, pear, marquise, trillion, and emerald, are also available, although these shapes are rarer in larger sizes.

Working with rubies can be challenging due to their pleochroic nature. In one crystal direction, rubies may appear red to purplish-red, while in another direction, they may appear orangy red. This makes it difficult to consistently orient the rough material for the ideal colour return. Considering the high value of rubies, cutters exercise great caution to avoid wasting material during the cutting process.

Ruby Carat Weight

When it comes to rubies, larger stones are generally rarer and more valuable than smaller ones. This is because larger rubies are less commonly found in nature, making them more sought after by collectors and enthusiasts. As the carat weight of a ruby increases, the price per carat can also increase due to their relative scarcity.

It’s worth noting that the price per carat for rubies can vary significantly based on other quality factors, such as colour and clarity. A smaller ruby with exceptional colour and clarity may command a higher price per carat than a larger ruby with lesser quality characteristics.

When considering the carat weight of a ruby, it’s important to strike a balance between personal preference and budget. The size of the ruby can impact its visual impact and presence in jewellery. However, it’s crucial to remember that the beauty and desirability of a ruby extend beyond its carat weight alone.

Ruby Care and Cleaning

Proper care and cleaning are essential to maintain the beauty and longevity of your ruby gemstone. While rubies are durable and resistant to scratches, they still require regular attention to preserve their brilliance and protect them from potential damage.

To care for your ruby, it’s important to avoid exposure to harsh chemicals. Keep your ruby away from household cleaning agents, bleach, and other abrasive substances, as they can cause damage to the gemstone.

Minimize the exposure of your ruby to high heat. It’s best to keep your ruby jewellery away from direct sunlight and high-temperature sources like hot stoves or open flames. Sudden temperature changes can also pose a risk, so it’s advisable to remove your ruby jewellery when engaging in activities that involve rapid temperature variations.

When cleaning your ruby, use a mild solution of warm water and a gentle liquid soap. Soak the ruby in the solution for about 30 minutes, and then use a soft brush, like a toothbrush, to gently scrub away any dirt or debris. Be sure to reach all the crevices and facets of the stone. After cleaning, rinse the ruby thoroughly with clean water and pat it dry with a soft, lint-free cloth. It’s generally not recommended to clean rubies using ultrasonic or steam cleaners.

Store your ruby jewellery with care. When you’re not wearing it, store it in a separate compartment or a soft pouch to prevent scratches and minimize contact with other jewellery. Even though rubies are relatively hard gemstones, they can still be susceptible to scratching if stored improperly.

Periodically have your ruby jewellery inspected by a professional jeweller. They can check for any loose stones, damaged prongs, or signs of wear. Professional jewellers can also provide specialized cleaning services to restore the brilliance of your ruby if needed.

Famous Rubies

Black Prince’s Ruby

Ruby Properties

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