Diamond Industry Glossary

 

A

Alluvial mining (Alluvial): Surface mining of stream/river bed deposits for minerals.

Artisanal mining (Artisanal): Small-scale, non-mechanized mining by individuals or small groups using simple hand tools.

Attributable share: When two (or more) companies own a mine, the attributable share is the percentage of production allotted to each.

Assortment: A collection of rough diamonds of various kinds, classified for sale.

 

B

Baguette cut (Baguette): Fancy cut. Rectangular in shape, with stepped faceting.

Bankability: Perceived financial health of a company in the eyes of financial institutions.

Beneficiation: Promotion of in-country wealth creation and skills development by supporting diamond-related activities in producer countries.

Best practice principles: Ethical, social, and environmental guidelines for responsible diamond business.

Blood diamonds (Conflict diamonds): Rough diamonds used to fund rebel activities against legitimate governments or produced under poor labor conditions.

Boart: Very low-quality diamond, usually used for industrial purposes.

Bourse: A trading floor where diamond dealers transact business.

Breakage: Rough diamonds breaking during processing.

Bricks and mortar: A physical retail store.

Brilliance: The intensity of reflections and fire coming from a diamond.

Brilliant cut (Brilliant): The most popular cut for a round stone, with 57 facets.

Bruting: Shaping the girdle by rotating one diamond against another.

 

C

4Cs: The four main characteristics defining diamond quality: carat, color, cut, and clarity.

CAGR: Compound Annual Growth Rate, measuring year-on-year percentage growth.

Carat: A unit of weight for diamonds and gemstones (0.20 grams).

Carat production: The amount of rough diamond carats extracted during mining.

Care and maintenance: A steady state where mining operations are suspended but can resume later.

Certificate: A grading report issued by a gemological authority detailing a polished diamond’s characteristics.

Certified diamond: A diamond graded by an independent gemological laboratory.

Chain of custody: Documentation tracing a diamond’s ownership history to verify authenticity.

Clarity: Standard characteristic measuring diamond imperfections.

Cleaving: Splitting a rough diamond along natural cleavage planes.

Clicks and mortar: A business model combining online and offline sales.

Colorless diamond: A clear or white diamond.

Comps: A company’s comparison of revenue and expenses over different periods.

Conflict diamonds: Rough diamonds used to fund rebel activities against legitimate governments or produced under poor labor conditions

Crown: The upper part of a polished diamond.

Culet: The facet at the bottom of a polished diamond’s pavilion.

Cut: The proportions and finish of a polished diamond.

Cutting and polishing: The process of preparing a rough diamond for use in jewelry.

CVD (Chemical Vapor Deposition): A process to create synthetic diamonds.

 

D

D-color, D-grade: The highest color grade for a diamond.

D-flawless: The highest combination of color and clarity grading.

Demand: Consumer and manufacturer demand for diamonds.

Diamantaire: A diamond trader.

Diamond: A naturally formed gemstone created over millions of years.

Diamond deposit (Deposit): A concentration of diamond-bearing rock.

Diamondiferous: Containing or yielding diamonds.

Diamond jewelry: Jewelry featuring diamonds.

Diamond Office: An Antwerp-based authority overseeing diamond imports and exports.

Diamond pipeline: The industry value chain from mining to retail.

Diamond recycling: The resale or trade-up of diamonds or jewelry.

Direct impact: The immediate economic impact of diamond mining.

Downstream: The retail end of the diamond industry.

 

E

EBIT: Earnings Before Interest and Tax, an indicator of profitability.

Excellent: A high standard of cut quality in a diamond.

Exploration: Activities undertaken to locate diamond deposits.

Extraction: The mining of diamonds.

Eye-clean: A diamond with no visible inclusions to the naked eye.

 

F

Facet: A flat plane on a diamond.

Fancy color (Fancies): Unusual colors such as pink, green, or blue.

Fancy shape: Any non-round diamond shape.

Feasibility study: A technical and economic evaluation of a diamond mining project.

Fine jewelry: Jewelry made with precious materials.

Fire: Flashes of spectral colors from a diamond.

Flaw: Internal or external characteristics of a diamond.

Flawless: A diamond with no inclusions or blemishes under 10x magnification.

Fluorescence: A diamond’s reaction to ultraviolet light.

 

G

GIA: Gemological Institute of America, a leading diamond grading authority.

Girdle: The outer edge of a diamond.

Grading: Assessing the characteristics of a diamond.

Gross Domestic Product (GDP): A measure of a country’s economic output.

 

H

Heart-shaped: A fancy-cut diamond resembling a heart.

HPHT (High Pressure High Temperature): A process to create synthetic diamonds.

 

I

Inclusions: Internal imperfections in a diamond.

Industrial diamonds: Diamonds used in industrial applications.

Investment diamond: A high-quality diamond bought for potential appreciation.

 

K

Kimberley Process (KP): A certification scheme preventing conflict diamonds from entering the market.

Kimberlite: A volcanic rock that sometimes contains diamonds.

 

L

Lab-grown diamond: A synthetic diamond with the same structure as a natural one.

Loupe: A 10x magnifying tool for examining diamonds.

 

M

Major miner: One of the largest diamond mining companies.

Melée: Small polished diamonds used in jewelry.

Midstream:The diamond value chain segment involves cutting, polishing, and wholesaling.

 

N

Nameplate (production, capacity): Intended full capacity production of a mining facility.

Near gem quality: A quality level between gem quality and industrial diamonds.

NGO: Non-governmental organization, non-profit group. In the diamond industry, it is seen as defending the interests of the local population and international oversight. 

 

O

Open-pit mining: Surface mining technique.

Oval cut: A type of fancy diamond cut.

 

P

Parcel: A batch of diamonds sold together.

Parcel paper: A folded piece of paper used to hold diamonds.

Pear cut: A fancy diamond cut.

Polished diamond: A cut and finished diamond ready for jewelry.

 

R

Rough diamond: A mined but uncut diamond.

Run-of-mine: The full assortment of diamonds produced by a mine.

 

S

Sight: A sales event by De Beers for contracted customers.

Sightholder: A De Beers-approved buyer.

 

T

Table: The largest facet of a polished diamond.

Triple X: A diamond graded excellent in polish, symmetry, and cut.

 

Y

Yield: The percentage of a rough diamond’s weight that becomes a polished gem.

 

 

Diamond Valuation

Valuation is a critical step in determining the worth of each diamond. Pricing is influenced by several factors, including weight (measured in carats) and market demand for specific sizes, colors, and qualities. Rarity significantly impacts value as well; for instance, diamonds with uncommon hues like pink or blue fetch premium prices. The projected yield and potential cutting outcomes further shape the stone’s valuation. Advanced technologies, such as X-ray fluorescence machines, optical scanners, and 3D mapping software, play a vital role in refining the process, ensuring precise sorting, and maximizing the stone's potential value.

Diamond Glossary
Beurs

How and Where are Rough Diamonds Traded?

Once sorted, rough diamonds enter the trading phase. 

Rough diamonds are primarily traded among industry professionals, including mining companies, manufacturers, and diamond dealers.

The global rough diamond trade operates through several channels:

  • Tender Systems and Auctions:

In tender systems and auctions, rough diamonds are offered to the highest bidder in a transparent and competitive environment. Buyers, often manufacturers or traders, have the opportunity to inspect and assess the stones

before placing sealed bids. Auctions are widely regarded as one of the fairest ways to sell diamonds, as the final price reflects true market demand.

Tender systems also allow smaller mining companies to bring their production to market efficiently. For instance, companies operating in Africa often use Antwerp as a venue to showcase and sell their rough diamonds in tenders.

  • Long-Term Supply Contracts:

Many major mining companies prefer long-term contracts with select clients, known as sightholders or contract clients. These agreements provide stability for both parties: the supplier is guaranteed regular sales, while the buyer secures a consistent supply of rough diamonds. This model is often used by larger players in the industry.

  • Open Market Transactions:

In the open market, diamonds are traded more freely, with brokers, traders, and smaller companies buying and selling parcels in secondary markets. These transactions often occur in trading hubs or at diamond bourses, which are highly secure exchanges specifically designed for the trade of diamonds.

Key trading centers around the world facilitate these transactions, with Antwerp standing out as a global leader. The city’s diamond district is home to numerous diamond companies, grading laboratories, and specialized trading offices.