選鑽石前你該知道的事：螢光反應是加分還是扣分？Is Diamond Fluorescence a Flaw or a Feature? A Buyer’s Guide

當你在選購鑽石時，有沒有想過什麼是螢光反應？根據業界標準，帶有螢光的鑽石到底是好還是壞？又該如何判斷自己的選擇是否正確？接下來JDC 將為你詳細講解螢光如何影響鑽石的外觀以及如何挑選適合自己的鑽石。

什麼是螢光反應？
螢光反應是指鑽石在強烈紫外光（UV）照射下，碳原子中的電子吸收高頻能量後，再釋放出可見光的現象。這種光通常呈藍色，但也可能出現其他顏色。市面上約有 25% 至 35% 的鑽石具有不同程度的螢光反應。

GIA 螢光等級分類
美國寶石研究院（GIA）會根據鑽石在長波紫外光下的反應強度，將螢光分為五個等級：

• None（無）：完全沒有螢光反應。
• Faint（微弱）：螢光非常微弱，肉眼幾乎看不見，僅在 UV 燈下會呈現淡淡的藍色光澤。
• Medium（中等）：比 Faint 更明顯的藍光，在 UV 燈下可見，但在一般光線下不明顯，可能略帶輕微混濁感。
• Strong（強烈）：在 UV 燈下呈現明顯且強烈的藍光，在自然光下可能出現較明顯的混濁感。
• Very Strong（非常強烈）：在 UV 燈下呈現飽和且突出的藍光，在自然光下常會導致鑽石出現明顯的乳白或混濁外觀。

那麽熒光反應是好是壞？
螢光本身並沒有絕對的好或壞，它是否適合，取決於鑽石的色階以及你的個人喜好。

💎 鑽石的色階D–F（無色）

這類鑽石在肉眼下呈現純淨透明，幾乎不帶任何黃調。螢光可能降低高色階鑽石的透明度，尤其在 D–F 色階中更容易顯現。

• None：完全無螢光，外觀純淨，不受影響。
• Faint：螢光極弱，通常不影響外觀，但仍建議檢查是否有輕微霧感。
• Medium：可能略微影響透明度，需留意是否出現輕微混濁。
• Strong / Very Strong：在自然光下可能出現乳白或霧感，降低鑽石的清澈度與純淨感。

總結：螢光強度越高，越可能影響高色階鑽石的清澈度與純淨感。

💎 G–J 色階（接近無色）

這類鑽石在肉眼看起來仍屬白色，僅在放大檢視下才會察覺些微黃調。螢光強度在此色階中可能提升白度，但需留意是否影響清澈度。

• None：保持原有白度，不受螢光影響。
• Faint：效果輕微，不明顯但不影響外觀。
• Medium：藍色螢光可中和淡黃，使鑽石顯得更白淨。
• Strong / Very Strong：中和效果更明顯，但可能伴隨輕微混濁，需視鑽石品質而定。

總結：適度螢光強度有助提升白度，但過強可能影響透明感。

💎 K–M 色階（淡黃色）

這類鑽石呈現暖色調，在白色金屬底托上尤為明顯，若搭配黃金色底托則更顯復古魅力。螢光強度有助於淡黃色鑽石提升白度，視覺效果更佳。

• None：保留原始黃色調，視覺上偏暖。
• Faint：中和效果有限，黃調仍明顯。
• Medium：藍色螢光可部分掩蓋黃調，使鑽石在特定光源下顯得更白。
• Strong / Very Strong：中和作用顯著，在紫外光下呈現更接近白色的效果，視覺提升明顯。

總結：螢光強度在低色階中有助中和黃調，提升整體白度與美感

在選購具有螢光性的鑽石時，建議親自觀察鑽石在不同光源下的表現。若你在實體店購買，可以請店員展示鑽石在紫外光（UV燈）和自然光下的外觀變化，幫助你判斷是否符合預期。若透過 JDC 網站選購，則可向賣家查詢鑽石在各種光線下是否會出現混濁感或色澤改變。了解螢光的影響，有助你挑選出真正適合自己、符合期待的鑽石。

When shopping for a diamond, have you ever wondered what fluorescence really is? Is a fluorescent diamond considered good or bad by industry standards? And how can you tell if your choice is the right one? In this guide, JDC will explain how fluorescence affects a diamond’s appearance and how to choose wisely.

What is fluorescence?
Fluorescence refers to the phenomenon where, under strong ultraviolet (UV) light, the electrons in a diamond’s carbon atoms absorb high-frequency energy and re-emit it as visible light. This light is typically blue, though other colors can occur. Approximately 25% to 35% of diamonds on the market exhibit some degree of fluorescence.

GIA Fluorescence Grading
The Gemological Institute of America (GIA) classifies fluorescence based on a diamond’s reaction to long-wave UV light, using five levels:

• None: No fluorescence at all.
• Faint: Very weak fluorescence, usually invisible to the naked eye. Under UV light, a subtle bluish glow may appear.
• Medium: More noticeable than Faint under UV light, but not visible in normal lighting. May cause slight haziness.
• Strong: A clear and intense blue glow under UV light. May result in visible cloudiness in natural light.
• Very Strong: A vivid and saturated blue glow under UV light. Often causes a pronounced milky or hazy appearance in daylight.

Is fluorescence considered good or bad?
Fluorescence itself isn’t inherently good or bad—it depends on the diamond’s color grade and your personal preferences.

💎 Color Grade D–F (Colorless)

These diamonds appear pure and transparent to the naked eye, with virtually no yellow tint. Fluorescence may reduce clarity in high color grades, especially in D–F diamonds.

• None: Completely clean appearance, unaffected by fluorescence.
• Faint: Very weak fluorescence, usually not noticeable, though slight haziness should still be checked.
• Medium: May slightly affect transparency; watch for subtle cloudiness.
• Strong / Very Strong: Can cause a milky or hazy look in natural light, reducing clarity and purity.

Summary: The higher the fluorescence intensity, the more likely it is to affect clarity and purity in high color grade diamonds.

💎 Color Grade G–J (Near Colorless)

These diamonds appear white to the naked eye, with only slight yellow tones visible under magnification. Fluorescence may enhance whiteness in this range, but clarity should still be considered.

• None: Maintains original whiteness, unaffected by fluorescence.
• Faint: Minimal effect, not visually noticeable.
• Medium: Blue fluorescence can help neutralize yellow tones, making the diamond appear whiter.
• Strong / Very Strong: Stronger neutralizing effect, but may also introduce slight haziness depending on overall quality.

Summary: Moderate fluorescence can enhance whiteness, but excessive intensity may compromise clarity.

💎 Color Grade K–M (Faint Yellow)

These diamonds have a warm tone visible to the naked eye, especially in white metal settings. Yellow gold settings enhance their vintage charm. Fluorescence can help improve visual whiteness.

• None: Retains original yellow tone, with a warmer appearance.
• Faint: Limited neutralizing effect; yellow tint remains noticeable.
• Medium: Blue fluorescence can partially mask yellow, making the diamond appear whiter under certain lighting.
• Strong / Very Strong: Significant neutralizing effect, especially under UV light, resulting in a visibly whiter appearance.

Summary: Higher fluorescence intensity helps counteract yellow tones, improving overall whiteness and visual appeal in lower color grades.

If you’re buying a fluorescent diamond in-store, ask the staff to show you how it looks under both UV light and natural light so you can observe the changes firsthand. If you’re purchasing through the JDC website, feel free to ask the seller about how the diamond performs under different lighting conditions, including whether it shows any cloudiness or color shifts. Understanding the impact of fluorescence will help you choose a diamond that truly meets your expectations.