Glossary

Plain-English definitions of the terms you'll meet when valuing precious metals and jewelry.

Karat (K)Fineness / millesimal marks Troy ounce (ozt)Pennyweight (dwt)Carat (ct)Spot price Melt value Alloy Plumb gold Hedging (purity hedging)Price multiplier Clarity & color (diamonds)Gem value matrix XRF / acid test

Karat (K): A measure of gold purity out of 24 parts. 24K is pure gold; 14K is 14/24 ≈ 58.3% gold with the balance made up of other metals for hardness and color. Not to be confused with carat, the gemstone weight unit.
Fineness / millesimal marks: Purity expressed in parts per thousand, stamped on the piece: 417 (10K), 585 (14K), 750 (18K), 917 (22K), 999 (24K) for gold; 925 (sterling) and 999 (fine) for silver; 900/950 for platinum. This stamp is usually the fastest way to identify an alloy.
Troy ounce (ozt): The standard unit for precious metal prices: 31.1035 grams — about 10% heavier than a regular (avoirdupois) ounce at 28.35 g. When you see "gold per ounce" in market news, it means troy ounces.
Pennyweight (dwt): 1/20 of a troy ounce ≈ 1.555 g. Common in the US jewelry trade — many buyers quote scrap prices per dwt.
Carat (ct): The gemstone weight unit: exactly 0.2 grams. A 1.0 ct diamond weighs 0.2 g. Spelled with a C — karat with a K is gold purity.
Spot price: The current market price for immediate delivery of a metal, quoted in USD per troy ounce. WITVT updates spot prices throughout the day — see the Metals page.
Melt value: What the precious metal content of an item is worth at spot price: net metal weight × purity × spot price. It ignores craftsmanship, brand, and antique value — a Cartier ring and a scrap band with the same gold content have the same melt value.
Alloy: A mixture of metals. Nearly all jewelry uses alloys — pure gold and silver are too soft. White gold, for example, mixes gold with white metals like silver, nickel, or palladium.
Plumb gold: Gold guaranteed to be at least the stamped purity (from "plumb" meaning exact). Marked 14KP or 585. The P does not mean plated.
Hedging (purity hedging): A small discount applied to cover uncertainty about an item's true purity, since stamps can overstate it. Configurable in workspace settings.
Price multiplier: A workspace setting that scales all calculated values — set 0.7 to model a buyer offering 70% of melt, or 1.0 to see full melt value.
Clarity & color (diamonds): The GIA grading dimensions WITVT uses for diamond matrices. Clarity runs from F/IF (flawless) through VVS, VS, SI to I (included); color runs from D (colorless) toward N (noticeably tinted). Together with cut and carat weight they determine a stone's matrix price.
Gem value matrix: Your own pricing table for diamonds: for each carat range, a grid of per-stone prices by clarity and color. WITVT multiplies nothing — it looks up the exact price you configured. Set up in Settings → Gem Matrices.
XRF / acid test: Ways to verify metal purity: an acid test kit (inexpensive, slightly destructive) or X-ray fluorescence analysis (non-destructive, used by refiners and serious buyers). Worth doing before selling high-value pieces.

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Glossary

Plain-English definitions of the terms you'll meet when valuing precious metals and jewelry.

Karat (K)

A measure of gold purity out of 24 parts. 24K is pure gold; 14K is 14/24 ≈ 58.3% gold with the balance made up of other metals for hardness and color. Not to be confused with carat, the gemstone weight unit.

Fineness / millesimal marks

Purity expressed in parts per thousand, stamped on the piece: 417 (10K), 585 (14K), 750 (18K), 917 (22K), 999 (24K) for gold; 925 (sterling) and 999 (fine) for silver; 900/950 for platinum. This stamp is usually the fastest way to identify an alloy.

Troy ounce (ozt)

The standard unit for precious metal prices: 31.1035 grams — about 10% heavier than a regular (avoirdupois) ounce at 28.35 g. When you see "gold per ounce" in market news, it means troy ounces.

Pennyweight (dwt)

1/20 of a troy ounce ≈ 1.555 g. Common in the US jewelry trade — many buyers quote scrap prices per dwt.

Carat (ct)

The gemstone weight unit: exactly 0.2 grams. A 1.0 ct diamond weighs 0.2 g. Spelled with a C — karat with a K is gold purity.

Spot price

The current market price for immediate delivery of a metal, quoted in USD per troy ounce. WITVT updates spot prices throughout the day — see the Metals page.

Melt value

What the precious metal content of an item is worth at spot price: net metal weight × purity × spot price. It ignores craftsmanship, brand, and antique value — a Cartier ring and a scrap band with the same gold content have the same melt value.

Alloy

A mixture of metals. Nearly all jewelry uses alloys — pure gold and silver are too soft. White gold, for example, mixes gold with white metals like silver, nickel, or palladium.

Plumb gold

Gold guaranteed to be at least the stamped purity (from "plumb" meaning exact). Marked 14KP or 585. The P does not mean plated.

Hedging (purity hedging)

A small discount applied to cover uncertainty about an item's true purity, since stamps can overstate it. Configurable in workspace settings.

Price multiplier

A workspace setting that scales all calculated values — set 0.7 to model a buyer offering 70% of melt, or 1.0 to see full melt value.

Clarity & color (diamonds)

The GIA grading dimensions WITVT uses for diamond matrices. Clarity runs from F/IF (flawless) through VVS, VS, SI to I (included); color runs from D (colorless) toward N (noticeably tinted). Together with cut and carat weight they determine a stone's matrix price.

Gem value matrix

Your own pricing table for diamonds: for each carat range, a grid of per-stone prices by clarity and color. WITVT multiplies nothing — it looks up the exact price you configured. Set up in Settings → Gem Matrices.

XRF / acid test

Ways to verify metal purity: an acid test kit (inexpensive, slightly destructive) or X-ray fluorescence analysis (non-destructive, used by refiners and serious buyers). Worth doing before selling high-value pieces.