Kamis, 12 Agustus 2010

What makes white gold different from regular gold?


Search
: white gold vs gold

Why
: Mom says, "It's just the color." Dad says, "It must be something in the makeup." I say it's some sort of alloy.

Answer
: An alloy! What a surprise. Info:

The gold content of yellow gold is measured in the same way it is measured in, for example, white gold. So an 18kt white gold ring contains 75% pure gold, just as 18kt yellow gold contains 75% pure gold.

The difference in color between yellow, white and rose is determined by the metals used in the alloy mix.

Yellow gold is made by mixing pure gold with alloy metals such as copper and zinc.

Rose gold is made using a mix of pure gold with alloys including copper. The copper provides the rose-reddish color.

White gold is an alloy of gold and some white metals such as silver and palladium.

Traditionally, nickel was used in white gold; however, nickel is no longer used in most white gold made today as nickel can cause reactions with some people.
Source: Gilletts

The More You Know: But what's a karat (or carat, if you're not in North America)? First, it comes from the Greek kerátion, “fruit of the carob,” from Arabic qīrāṭ and Italian carato. Carob seeds were once used as weights on precision scales because of their reputation for having a uniform weight (sorta - there's more here if you have nothing better to do).

Then:
The carat is a measure of the purity of gold alloys.

As a measure of purity, one carat is \tfrac{1}{24} purity by mass:

X = 24\,\frac{M_g}{M_m}

where

X is the carat rating of the material,
Mg is the mass of pure gold or platinum in the material, and
Mm is the total mass of the material.

Therefore 24-carat gold is fine (99.9% Au w/w), 18-carat gold is 75% gold, 12-carat gold is 50% gold, and so forth.

Lol, do what nah?

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