Lab diamonds and other white, colorless gemstones, such as moissanite, are highly sought-after diamond alternatives. Understanding their differences is crucial for consumers purchasing sustainable, ethical, or affordable substitutes.

Lab-grown diamonds and moissanite diamonds are similar in appearance, but very different. This article will explore the differences and help you make an informed choice as to which gemstone is best for you.

• TABLE OF CONTENTS

1. What are Lab Diamonds？
2. What is Moissanite？
3. The Difference Between Moissanite and Lab Diamonds
4. Moissanite vs. lab diamond: which one should I choose?
5. Maintenance Tips
6. Other natural diamond alternatives

1. What are Lab Diamonds?
Laboratory-grown diamonds offer consumers the same choice as natural diamonds. These diamonds are identical to natural diamonds in terms of chemical composition, optical properties, and physical characteristics, being composed of pure carbon and exhibiting a lattice structure. Laboratory-grown diamonds are created by simulating the extreme temperature and pressure conditions under which natural diamonds are formed deep within the earth and are grown from carbon dioxide molecules using either High Pressure High Temperature (HPHT) or Chemical Vapor Deposition (CVD) techniques. As a result, these man-made diamonds are identical to mined natural diamonds in terms of hardness, brilliance, and sparkle.
There are no chemical differences between lab-grown and naturally mined diamonds - they are all crystal clear carbon. Not only do they use the same grading system and certification process, but they are also cut and polished the same. They are undoubtedly an ideal alternative for consumers who wish to purchase a genuine diamond.
2.What is Moissanite?
Moissanite was discovered by chance in 1893 when French scientist Henri Moissan first discovered this gemstone particle composed of silicon carbide (SiC) in a meteorite crater in Arizona. Due to its extraterrestrial origins, natural moissanite is extremely rare. Although natural moissanite does exist, its crystals are too small to be used in jewelry making, so almost all moissanite sold on the market comes from laboratory production.
Unlike lab-grown diamonds (which have the same chemical composition as natural diamonds), moissanite contains silica and carbon, which gives it a higher refractive index than diamonds. This gives moissanite a more brilliant brilliance than diamonds, but diamonds are preferred for their colorless sparkle. Although moissanite is slightly less hard than diamonds, it is still quite hard, has a cut similar to diamonds, is usually 15% lighter than diamonds, and is an excellent alternative to natural or lab-grown diamonds.
3. The Difference Between Moissanite and Lab Diamonds

• Specific Gravity: There is a clear difference between moissanite and diamond-specific gravity. While diamonds have a specific gravity of 3.52, moissanite has a specific gravity of only 3.22, which is about 15% lighter. This difference makes it easy to distinguish between the two stones when they are not set, by using a specific gravity solution of methyl iodide (specific gravity 3.32). This simple specific gravity test clearly distinguishes lab diamonds from moissanites.
• Hardness: Diamond is undoubtedly the hardest natural substance on earth. Measured according to the Mohs hardness scale, laboratory-grown diamonds reach a maximum hardness of 10, while moissanite diamonds have a hardness of 9.25, which is slightly lower than diamonds. This small but significant difference means that a scratch on the surface of a moissanite diamond with a diamond hardness tester will leave a mark, whereas a diamond will leave no mark at all.
• Sparkle: In a darker environment, when a flash lamp is used to illuminate diamonds and moissanite diamonds respectively, the observer can feel the obvious difference in the fire color effect between the two. Moissanite's fire is more than twice as intense as that of diamonds, which gemmologists refer to as “dispersion”. Moissanite has a dispersion coefficient of 0.104, compared to 0.044 for diamonds, so when juxtaposed with a lab diamond, moissanite shines like a firework, and is even more brilliant than a lab diamond.
• Cut: unlike diamonds, which have sharp prongs, most cut and polished moissanite has a more rounded edge of the prongs. This is a clear difference between the two stones in the cutting process. Diamonds have relatively sharp prongs, whereas moissanite has a more rounded prong pattern after cutting.
• Inclusions: diamonds and moissanite in the internal structure of the obvious differences. Diamonds are usually cleaner on the inside, with few visible inclusions. On the other hand, all authenticated moissanite will contain some inclusions, usually in the form of a needle-like parallel arrangement. Subtle parallel reflective lines can also be seen under magnification.
• Polishing Lines: moissanite girdle polishing lines will show the characteristics parallel to each other, which is completely different from the diamond polishing lines. Diamonds require constant adjustment of the polishing direction during the polishing process to ensure that the effect of each facet is harmonized. Moissanite, on the other hand, can be polished continuously in the same direction, especially between neighboring facets, where the difference is more pronounced.
• Refraction: The refractive properties of gemstones are an important basis for distinguishing between different gemstones. Moissanite and diamond differ significantly in this respect. Diamonds have a refractive index of 2.42, which is consistent whether natural or laboratory-made. Moissanite, on the other hand, has a refractive index range of 2.65-2.69, which is significantly higher than that of diamonds. This difference in refractive properties also contributes to the difference in reflectivity between the two stones.
• Conductivity: According to the GIA report, 80% of moissanite are electrical conductors (natural diamonds only blue, blue-gray type IIb diamonds with conductivity). Common white/light yellow color diamonds are not conductive, so the conductivity meter or moissanometer can be used to identify diamonds and moissanite.
• Birefringent Properties: diamonds are monorefringent, while moissanite is birefringent. This means that when you look closely at moissanite, especially at the prongs and the tip of the base, you will see the phenomenon of ghosting. This ghosting effect persists even when the viewing angle is changed. In addition to moissanite, other gemstones such as sapphire, tourmaline, and zircon exhibit similar birefringent properties.
• Price： Although laboratory-grown diamonds are generally less expensive than natural diamonds, their final cost is still largely determined by the well-known “4Cs” of carat weight, cut precision, color, and clarity. Moissanite gemstones are much less expensive than both natural and laboratory-grown diamonds, and their cost is largely influenced by size, color, and clarity.
  

4. Moissanite vs. lab diamond: which one should I choose?
When choosing between moissanite and lab-grown diamonds, the following factors need to be considered.

• Budget: Moissanite is usually more affordable than lab diamonds and is suitable for consumers on a budget. Laboratory diamonds are less expensive than natural diamonds, but still more expensive than most moissanites.
• Aesthetic Preferences: Moissanite's unique optical properties, such as refractive index and birefringence, create a distinctive visual effect. Laboratory diamonds provide a classic diamond look similar to that of natural diamonds.
• Brand recognition: As the traditional jewelry of choice, diamonds have a strong brand influence and are widely recognized and accepted. Moissanite, as an emerging gemstone, is relatively less well-known but is gradually gaining popularity and recognition.

Taking all these factors into consideration, consumers with smaller budgets and a taste for unique gemstones may prefer moissanite. For those who prefer the classic image of diamonds and brand influence, lab-grown diamonds may be a better choice. In the end, we still need to make a judgment based on personal aesthetic preferences and usage scenarios (e.g., lab diamonds are more suitable for engagement ring main diamonds).
5. Maintenance Tips
For laboratory diamonds, cleaning with mild soapy water and gentle brushing with a soft bristle brush can effectively remove surface dirt. Avoid contact with strong acids and alkalis, they may corrode the metal setting part of the diamond. When stored, place separately in a soft cloth bag or jewelry box compartment, to prevent

6. Other natural diamond alternatives
Moissan diamonds are similarly cared for and can also be cleaned with mild detergents. However, due to its slightly lower hardness, it is more important to avoid collision with hard gemstones or sharp edges of metals when storing and wearing, so as not to produce scratches that affect the aesthetics.
Other natural diamond alternatives

• Cubic Zirconia: Cubic Zirconia (CZ) is known as one of the most affordable diamond imitation options on the market, but it is less hard and durable, and its fire and sparkle naturally dim over time.CZ is better suited for fashion jewelry but is not recommended for any jewelry that requires long-term durability, including engagement rings or side stones.
• White Sapphire: The problem with white sapphires compared to lab-grown diamonds is that they have more inclusions, which affects their brilliance, and they lack the iridescent sparkle of diamonds. The advantage of white sapphires is that they are more affordable than lab-grown diamonds and are not less durable. White sapphires are also not ideal for engagement rings, as they darken over time, require frequent cleaning, and can be disappointing in appearance.
• White Topaz: Since white topaz is a natural gemstone, internal flaws may occur during its formation. With a Mohs hardness of about 8, it is softer than a diamond and can be easily scratched and chipped. It is also sensitive to high temperatures and will gradually lose its luster and color over time. White topaz may appear more transparent and glassy than white sapphire, but has the same hardness and durability issues and is less suited to jewelry that needs to be worn for long periods, such as engagement rings.