Yes, "fake" diamonds, especially simulants like cubic zirconia (CZ) and glass, can turn yellow or cloudy over time due to dirt buildup or material degradation, while lab-grown diamonds (which are real diamonds) are very durable but can show color shifts from extreme heat or treatment, though regular cleaning usually restores their appearance.
This yellow hue is typically caused by the presence of nitrogen atoms within the diamond's atomic structure, which absorb blue light and give the stone a warmer appearance. The more nitrogen present, the more noticeable the yellow tint becomes.
Lab-grown diamonds do not change color over time as part of normal wear and tear due to being chemically identical to mined stones; lab diamonds offer equal durability and color stability as their counterparts in terms of chemical makeup and durability.
Natural yellow diamonds form over millions of years under intense pressure and heat deep within the Earth. They are prized for their authenticity, rarity, and natural origin, making them a coveted choice for collectors and traditionalists.
White gold will yellow a bit when its rhodium coating wears off, revealing the natural color of the gold. Exposure to detergent, chemicals, and sweat can speed up white gold yellowing. The only way to fix a yellowing white gold ring is with rhodium replating — cleaning and polishing won't change the color.
The cheapest color diamonds tend to be light yellow and brown diamonds. These can often be found at lower price points compared to colorless diamonds.
Gemologists and professional jewelers cannot distinguish between a lab-created diamond and a natural one through the naked eye. They would need a powerful microscope, specialized equipment, and laser-inscribed markings to look for the minuscule differences that indicate how the diamond was formed.
Mobile apps may mimic testing, but they can't match the accuracy of professional instruments. Your phone won't replace a professional appraisal, but it can assist. Use the flashlight to observe how the stone handles light. A real diamond will produce sharp flashes and concentrated brilliance.
The Sparkle Test
Synthetic or fake stones, sparkle less than real, or mined diamonds. With light reflection, look for shades of gray. Synthetic stones, such as cubic zirconia, sparkle with more iridescent colors. Natural diamonds reflect light in more grayish hues.
Flashlight Test
To tell if a diamond is real with a flashlight, observe how the stone refracts light. Shine a flashlight directly at the diamond. A real diamond will reflect white light brilliantly, while a fake stone may not reflect as intensely or at all.
Most CZ can be described as colorless, and most have high clarity with minute, if any, imperfections. CZ will, however, yellow in color over time. CZ has slightly more fire but less brilliance than diamond. Cubic zirconia can be produced in almost any color.
Pure yellow diamonds, due to their color, are oftentimes called canary yellow diamonds. Another nickname some use for these sunny stones is Zimmy. This name comes from a specific type of yellow gemstones that are produced from the Zimmy diamond mine in the Sierra Leone.
You can pay between $3,000 and $3,500 per carat for a "decent quality" yellow diamond. A gem of 4.38 carats and $3,500 per carat could be worth $15,330 if Wredberg's diamond falls into that category.
Costco sells diamonds with a cut grade of Good to Excellent. Although treating diamonds is an accepted practice among many jewelers, Costco only sells natural and untreated diamonds.
Types of Diamond Cuts and Their Characteristics
Round brilliant is the most popular and highly sold cut. Its brilliance and symmetry make it timeless. Because of its strong demand, it commands the highest resale value.
For $5,000, you can get a high-quality 1+ carat diamond and a beautiful solitaire, pavé, halo, or side-stone engagement ring.
You can buy a large authentic center diamond for under $500, but it is likely to have very low cut, color and clarity grades. This means the stone will not reflect light well, may have some inclusions and a gray or yellow tint. A larger, lower cost diamond may also be less durable.
In order to assess the grades of colour, coloured diamonds are placed into one of nine categories: faint (least valuable), very light, light, fancy light, fancy, fancy dark, fancy intense, fancy deep and fancy vivid (the rarest and most expensive).