Tag: Rough Diamond

Key Characteristics of Chameleon Diamonds:
Colour Change:

Chameleon diamonds typically shift from an olive green or grayish-green hue to a yellow or orangey-yellow shade when exposed to heat (approximately 150°C) or left in darkness for an extended period.
Once cooled or exposed to light again, they revert to their original colour.
Thermochromic & Photochromic Properties:

The colour change can occur due to both heat (thermochromism) and darkness/light exposure (photochromism), making them unique among diamonds.
Rare Chemical Composition:

Scientists believe the colour change is due to a combination of hydrogen, nitrogen, and possibly nickel impurities within the diamond’s crystal structure.
Not a Fancy Colour Diamond:

Unlike standard fancy colour diamonds, which have a fixed hue, chameleon diamonds possess a dynamic, temporary colour change.
Value & Rarity:

Due to their scarcity, chameleon diamonds are highly prized by collectors and diamond enthusiasts.

Unlike standard fancy colour diamonds, which have a fixed hue, chameleon diamonds possess a dynamic, temporary colour change.

Value & Rarity:

Due to their scarcity, chameleon diamonds are highly prized by collectors and diamond enthusiasts.

A cavity is a type of diamond inclusion that appears as an opening or large indentation on the surface of a diamond. It occurs when a small part of the diamond is removed, often due to the detachment of another inclusion (such as a crystal or feather) during the cutting or polishing process.

Key Characteristics of Cavity Inclusions in Diamonds:
How Cavities Form

They usually form when a weak area of the diamond, such as an internal inclusion, falls out during cutting, polishing, or wear.
Can also result from the removal of a feather (crack) or crystal inclusion.
Impact on Diamond Quality & Value

Visibility: Cavities can be noticeable, especially if they are large or located in a prominent position.
Durability Concern: A deep cavity can make a diamond more vulnerable to chipping or further damage over time.
Clarity Grade Reduction: Diamonds with significant cavities may receive a lower clarity grade from the GIA (Gemological Institute of America).
Where Cavities Are Found

They can appear anywhere on the diamond, but those near the edges or girdle are less concerning than those in the center (table).
How to Minimize the Effect of Cavities

Strategic Setting: A prong or bezel setting can hide a cavity located near the edge.
Polishing & Recutting: If the cavity is shallow, a jeweler may be able to polish or recut the diamond to remove or reduce its appearance.
Avoiding Further Damage: Regular cleaning and careful handling can help prevent dirt from accumulating inside the cavity, which can make it more visible.

Key Facts About Carat Weight:
Definition

One carat is equal to 200 milligrams (0.2 grams).
It is subdivided into 100 points, meaning a 0.50-carat diamond is also called a 50-point diamond.
Origin of the Term

The term “carat” comes from the carob seed, which was historically used as a reference for weighing gemstones due to its uniform weight.
Carat vs. Size

While carat refers to weight, it does not always indicate a diamond’s physical size.
Different cuts and shapes can make a diamond appear larger or smaller than another of the same weight.
Impact on Price

Diamond prices increase significantly with carat weight, especially at milestone sizes (e.g., 0.50 ct, 1.00 ct, 1.50 ct, 2.00 ct).
Larger diamonds are rarer and more expensive per carat than smaller ones.
Carat Weight vs. Other Cs

A diamond’s cut, colour, and clarity also play a major role in its overall value and appearance.
A well-cut 0.90-carat diamond can appear nearly the same size as a 1.00-carat diamond but at a lower cost.

Small black graphite inclusions in a diamond are a type of natural impurity that occurs during the diamond’s formation process. These inclusions can affect the diamond’s clarity, appearance, and value.

Key Facts About Black Graphite Inclusions in Diamonds:
What Are They?

Black inclusions are tiny particles of graphite or other carbon-based minerals trapped inside the diamond during its crystallization.
They appear as small black spots, specks, or clusters within the stone.
Impact on Clarity & Value

Diamonds with large, visible graphite inclusions receive lower clarity grades from the GIA (Gemological Institute of America).
If the inclusions are numerous or positioned near the surface, they can reduce transparency and brilliance.
However, some graphite inclusions are microscopic and do not impact the stone’s beauty significantly.
Types of Graphite Inclusions

Pinpoints – Tiny black dots only visible under magnification.
Clouds – Groups of small inclusions that create a hazy effect.
Needles or Veins – Thin, elongated graphite inclusions.
Carbon Spots – Larger black inclusions visible to the naked eye.
Are They a Problem?

If inclusions are small and well-placed (e.g., near the edges), they may not significantly affect the diamond’s beauty.
However, large or centrally located inclusions can impact transparency, sparkle, and durability.
How to Minimize Their Appearance

Cut Quality Matters – A well-cut diamond with a brilliant faceting pattern (e.g., round brilliant) can hide inclusions.
Setting Choice – Prongs and bezels can mask inclusions near the edges.
Clarity Enhancement – Some diamonds undergo laser drilling or fracture filling to reduce the visibility of black inclusions.

A broad scale of diamond colour grades that ranges from a near colourless, almost undetectable pale yellow to increasingly tinted yellow. Once it has enough yellow saturation to qualify as a fancy colour, it is no longer called a Cape Series diamond.

Cape Series Diamonds refer to a category of diamonds that exhibit a noticeable yellow or brown tint due to the presence of nitrogen in their crystal structure. The term originates from the Cape Province of South Africa, where these diamonds were historically mined in large quantities.

Characteristics of Cape Series Diamonds:
Colour Range

These diamonds fall within the near-colourless to light yellow range on the GIA D–Z colour scale.
They typically appear in the K to M range, but some can extend beyond, showing a deeper yellow tint.
Unlike Fancy Yellow Diamonds (such as Canary Diamonds), Cape Series Diamonds do not have the intense saturation needed to be classified as “fancy colour diamonds.”
Cause of Yellow Tint

The yellowish hue comes from nitrogen impurities, which absorb blue light and make the diamond appear slightly yellow.
The higher the nitrogen concentration, the stronger the yellow tint.
Historical Significance

The name “Cape Series” comes from South Africa’s Cape Province, where many of these diamonds were first discovered in the late 19th century.
These diamonds were highly valued in the early days of diamond mining, especially before the discovery of purer, colourless diamonds.
Market Perception & Value

Higher Colour Grades (K–M): Often sold at a discount compared to colourless diamonds (D–F), making them an affordable option for buyers.
Lower Grades (N–Z): Can exhibit a stronger yellow tone, appealing to those who prefer warm-toned diamonds.
Well-cut Cape Series Diamonds can still appear brilliant, especially in round brilliant and cushion cuts, which minimize visible colour.
Modern Use

Many Cape Series Diamonds are set in yellow gold settings to enhance their warmth and reduce contrast.
Some are reclassified as “faint yellow” fancy diamonds if their colour saturation is strong enough.