METAL INFORMATION
Metal Types • Gold
Alloys • Melting Points • Weights
& Conversions
Metal Types
NOBLE METALS |
Metals that resist oxidation or corrosion; Gold, Silver and Platinum. |
PLATINUM |
90% fine platinum and usually 10% iridium. |
PALLADIUM |
95% pure palladium and 5% ruthenium. |
GOLD FILLED or GOLD OVERLAY |
Made by joining a layer of gold to a base metal alloy. In the U.S., layer of gold must
equal at least 1/20 of the total weight of the metal in the piece. |
ROLLED GOLD PLATE |
The same as gold filled, but usually of lower quality. Gold can be as little as 1/30th
or even 1/40th of the total weight. |
GOLD ELECTROPLATE |
Made by electrolytically depositing very little gold on a base metal. |
GOLD LEAF, WASH or FLASH |
An extremely thin coating 1/2000,000 to 1/250,000th of an inch. |
VERMEIL |
Electroplating or bonding over sterling silver with at least 1/20 millions of an inch
of gold. |
STERLING SILVER |
925/1000 (92.5%) fine silver and 75/1000 (7.5%) copper. |
COIN SILVER |
900/1000 (90%) fine silver & 100/1000 (10%) copper. This cannot
be called sterling. |
BRITANNIA SILVER |
Must be at least 95.84% pure silver by weight. |
PEWTER |
Tin, copper and antimony composition similar to Britannia metal. |
BRITANNIA METAL |
Composition of tin, copper and antimony. |
MEXICAN SILVER |
Usually contains 95% silver and 5% copper; more pure than sterling. (Not all silver
produced in Mexico is Mexican Silver). |
NICKEL and/or GERMAN SILVER |
Neither contains any silver. Nickel, copper & zinc. |
SOLID GOLD |
Only refers to construction (most likely not hollow). |
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Gold Alloys
Gold will NEVER turn a finger or neck
dark - it is the alloy mixed with the gold that does the turning. Sometimes it is only
temporary due to the person's internal chemistry from a stressful situation, food or
medicine that was recently ingested. |
Pure gold is too soft to wear as jewelry so it is alloyed (mixed) with other metals to
make it more durable. |
Gold Alloys |
European |
| 24 karat is pure gold |
.999 |
| 18 karat is 18 parts gold & 6 parts alloy |
.750 |
| 16 karat (Dental) is 16 parts gold & 8 parts alloy |
|
| 14 karat is 14 parts gold & 10 parts alloy |
.585 |
| 10 karat is 10 parts gold & 14 parts alloy |
.416 |
Most yellow gold contains varying amounts of copper & silver. |
Most white gold contains varying amounts of nickel, zinc & copper. |
Silver and zinc tend to give gold its green color, Copper - Red and Nickel its white
color. |
Melting Points
10k gold
14k gold
18k gold
24k gold |
1665°
1615°
1700°
1945° |
Platinum
Silver sterling
Silver pure |
3250°
1640°
1760° |
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Weights
| ct |
= |
Carats - used in weighing Gemstones |
| kt |
= |
Karat - used in weighing Metal |
| g |
= |
Gram |
| dwt |
= |
Pennyweight |
| gr |
= |
Grain |
Conversions
1 Dwt |
= |
1.555 grams |
1 Dwt |
= |
.05 troy ounces |
20 Dwt |
= |
1 troy ounce |
3.25 Dwt |
= |
5.05 grams |
8 Dwt |
= |
12.44 grams |
1 Avoir oz |
= |
28.35 grams |
1 Avoir oz |
= |
18.22917 dwt |
1 Avoir oz |
= |
141.75 ct |
1 Troy oz |
= |
31.103481 grams |
1 Troy oz |
= |
155.51 ct |
1 Gram |
= |
.03215 troy oz |
1 Gram |
= |
.643 dwt |
1 Gram |
= |
.03527 Avor oz |
1 Gram |
= |
5 ct |
1 Carat |
= |
0.00705478 Avor oz |
1 Carat |
= |
1/5 of a Gram |
1 Carat |
= |
.1286 dwt |
|
TO CONVERT
Carats to Dwt x by .12860
Carats to Grams x by .2
Dwt to Carats x by 7.776
Dwt to Grams x by 1.5552
Dwt to Troy oz x by .05
Grams to Carats x by 5.0
Grams to Dwt x by .64301
Avoir Oz to Troy oz x by .91146
Avoir Oz to Grams x by 28.3495
Troy Oz to Avoir oz x by 1.091 |
1 Avoirdupois pound = 14.583 troy ounces
1 Troy ounce is about 10% heavier than the common Avoirdupois ounce.
Avoirdupois is the system of weights using the pound of 16 ounces.
Troy weight is the system of weights used for gold or silver with twelve ounces to the
pound.
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