Gemstones have long held a significant place in human history and culture, admired for their exceptional beauty and allure. Among these precious gems, rubies stand out with their vivid red color and unparalleled rarity. While polished and faceted rubies are often seen in jewelry, the uncut form of this gemstone possesses its own unique charm. In this comprehensive guide, we will delve into the world of uncut rubies, exploring their physical characteristics, natural formations, and providing detailed insights on how to identify them.
1. The Raw Beauty of Uncut Rubies:
Uncut rubies, also known as rough rubies or raw rubies, refer to the natural state of the gemstone before it undergoes cutting, shaping, and polishing processes. Unlike their polished counterparts, uncut rubies display a rough, unrefined appearance. Their surface may be uneven, with jagged edges and irregular shapes. Uncut rubies often exhibit a deep red color, although variations in hue and intensity are common.
2. Physical Characteristics of Uncut Rubies:
2.1 Color:
The most distinguishing feature of rubies, whether cut or uncut, is their captivating red color. Uncut rubies can range from a vivid, intense red to a slightly pinkish or purplish hue. This characteristic red color is primarily attributed to the presence of chromium within the crystal lattice structure of the gemstone. The intensity and saturation of the red color in uncut rubies depend on the concentration of chromium and can vary from gem to gem.
2.2 Transparency and Clarity:
Uncut rubies are typically translucent to opaque, meaning that they allow some light to pass through but do not exhibit the same transparency as faceted gemstones. In their uncut state, rubies often contain natural inclusions and impurities, which can affect their clarity. These inclusions are formed during the gemstone’s growth process and are unique to each individual ruby. While flawless uncut rubies are rare, the presence of inclusions does not necessarily diminish their value or beauty.
2.3 Shape and Texture:
Uncut rubies occur naturally in various shapes, including rough angular fragments, irregularly shaped crystals, or elongated formations. Their texture is rough, with a grainy or crystalline surface that reflects their untamed origin. The surface may be etched, pitted, or marked due to exposure to external elements during their formation and geological journey.
3. Formation of Uncut Rubies:
Uncut rubies are created through complex geological processes that occur deep within the Earth’s crust. Rubies belong to the corundum mineral family, and their formation requires specific conditions of temperature and pressure. Most rubies are formed within metamorphic rocks, such as marble and schist, or in igneous rocks, like basalt. The process involves the presence of aluminum oxide and the incorporation of chromium and other trace elements during crystal growth. Over millions of years, geological forces and volcanic activities bring these rubies closer to the surface.
4. Identifying a Raw, Uncut Ruby
4.1 Ideal Shape
It is much easier to tell if a ruby is real when it is raw and uncut, for a variety of reasons. Rubies like to grow in a flat, hexagonal shape. If the uncut gem shows this natural growth characteristic, along with parts of its host rock (marble or alkali basalt) still attached, it is very likely it is a real ruby. Rubies are also very heavy for their size.
4.2 Non-Ideal Shape
There can be problems with identifying the raw ruby based only on the growth since they do not always form like this. Nature almost never makes anything uniform, especially gemstones. Most of them form in a super-heated slurry of various elements making inclusions and weirdly shaped rough very common.
Rubies can also show up in places like Sri Lanka as water-worn pebbles, making identification by the original crystal shape nearly impossible. Despite being weathered and broken up over time, they may appear shallow in this form too. Unfortunately, only first-hand experience and general training can aid in a definitive ID of the gem at this point. Thankfully there are other ways of checking the gemstones.
4.3 Reviewing Inclusions
An additional way to check is to try and look at inclusions, the stuff that forms inside a ruby. They will often have crystals, with silk and fingerprints being especially common for them. Often the crystal surface will be cloudy, making it difficult to use a loupe and look inside without a window being polished on the surface. This is frequently done by cutters to evaluate how they want to cut rubies and various other gemstones.
4.4 Streak Test
One test is called the streak-test, and it is not done to faceted rubies because it is destructive and scratches the polish. For uncut gems where the surface is cut away this is not a problem.
This test only works on gemstones with a hardness of 6 or lower, and involves dragging them across an unglazed, porcelain (white or black) plate. The streak left behind will show what the inherent color of the gem is. If any streak is left behind on a plate by an uncut ruby and not some of the rock material that might still be attached to it, that is not a ruby. Rubies have a hardness of 9, and the plate will only scratch stones with a hardness of 6 or less.
The only way to check harder minerals is to pulverize a piece and smear the powder on the plate. A ruby’s streak would be colorless because their color is caused by trace amounts of chromium. The red color is not an inherent part of its basic chemical structure.
5. Combine Techniques
Many times ruby buyers and cutters will use a variety of these identification techniques to check gemstones (primarily appearance and inclusions), though highly experienced tradesmen rarely find evidence to contradict their first-impression. Well formed rubies can be verified at a glance, but a buyer should always check a few factors.
Beware large, super-clear rubies, especially if they are cheap. These are certainly synthetic rubies, and any natural ruby rough like that will be extremely expensive and have accompanying papers with one or more accredited gemological laboratories that you can contact and verify.
6. Conclusion:
Uncut rubies possess a raw and natural beauty that appeals to gemstone enthusiasts and collectors. Their rough appearance, vibrant red color, and unique formations make them captivating and sought-after gemstones. Identifying uncut rubies requires attention to their color, transparency, texture, weight, and other physical characteristics. By understanding the features and origins of uncut rubies, you can appreciate their innate allure and gain insights into the fascinating world of gemstones. Whether you prefer them in their raw form or marvel at their polished brilliance, rubies continue to enchant us with their timeless charm and captivating allure.
