Chrysoberyl Cat’s Eye - The king of cat's eyes

Chrysoberyl Cat's Eyes are renowned for their mesmerizing chatoyant effect, a result of fascinating geological processes spanning thousands of years. A gem as enigmatic and captivating as a real feline's eye, and one of the five treasures among precious gemstones.

Optical phenomenon chatoyancy phenomenon

Many gemstones exhibit the optical phenomenon known as chatoyancy or the "cat’s eye effect" when cut in cabochon(a dom-shaped cutting). Among them, the Chrysoberyl Cat’s Eye is considered one of the most valuable for collection and appreciation. The cat’s eye effect presents as a single line that runs across the surface of the stone and shifts as the stone is rotated. This particular effect occurs due to parallel inclusions of tubes or fibers within the stone.

Similar to this bundle of threads, we can imagine the thin, parallel, and orderly inclusions within the gem. When light shines on it and we move the bundle of threads under the beam, the "cat's eye effect" becomes visible. This strip of light is known as chatoyancy.

In an exceptional Chrysoberyl Cat’s Eye, the bright band must be straight and highly prominent. This luminous band should stretch all the way to the bottom when you tilt the gemstone and observe it from the gem’s side profile.

When you shine a beam of light vertically onto the gem and illuminate it, you'll sometimes notice a "milk and honey" visual effect(one side of the gem will appear milky white, while the other side retains its golden hue). But there is another optical phenomenon, which is the "open and close".

The phenomenon of opening and closing occurs when you shine two light sources on the gemstone at a 45-degree angle, causing the line to appear to open and close in response to the light source's movement, it splits into two bands that move apart and back together as if the stone is winking at you ;)

Let’s start with color:

Chrysoberyl Cat’s Eye showcases hues ranging from honey yellow to brownish yellow, yellow, and even yellowish-brown and grayish green. However, honey color is the most sought-after in the market, followed by green, with the darker brown shades coming in third. If the colour appears to be too light or exhibits hints of brown or off-white tones, its market value can diminish.

Look at the line:

Keep these 5 keywords in mind: Straight, Bright, Centered, Lively, and Refined.

Straight implies that the line should be as straight and crisp as possible(as in the image above). Bright suggests that the line should be particularly bright when viewed under strong lighting conditions. Centered emphasizes the importance of positioning the line as centrally as possible; however, achieving straightness and centering may pose a challenge if the inclusions are not perfectly aligned.

Lively means the line should gleam brilliantly under intense light. Refined underscores the necessity of maintaining a thin and sharp appearance, avoiding excessive thickness or bluntness to convey a beautiful and sophisticated bright band.

The cut

Have you noticed that nearly all gemstones exhibiting the chatoyancy effect are predominantly cut into cabochons? Ever wondered why this is the case?

The rationale behind this lies in the fact that cabochon-shaped gemstones excel in capturing light, requiring the bright bands to be precisely concentrated on the curved surface's apex. The bottoms generally retain their original appearance and are not polished. The purpose behind this is to enhance the clarity of the line and imbue it with a clearer appearance, should you notice that the bottom of the cat's eye gemstone is exceptionally smooth, clean, and neat, exercise caution as it could potentially indicate a counterfeit.

When compared to precious gems like Diamonds, Rubies, Sapphires, and Emeralds, Chrysoberyl Cat’s Eyes are relatively rare in occurrence. One of the primary factors contributing to this scarcity is their limited production. This rarity is precisely why Chrysoberyl Cat’s Eyes are highly sought after and cherished by jewellry collectors as prized favorites.

Have a sparkling rest of the week!

Shine on,

Hanna Ho