The second is called white gold yellow gold is known, but it is covered with a layer of Platinum, this wear it haraam for men, because a man dressed up as yellow gold, and wear it haraam for men, according to scholarly consensus, as stated by al-Nawawi in Sharh Saheeh Muslim.
Third: called white gold yellow gold is known, but mixed with a certain percentage of "Palladium" or other, more or less depending on the caliber of gold required to get it, this is the famous known gold shops.
And that – according to experts-: you are to set up a kilo of gold 21 mix 875 kg of pure gold (24) 125 grams of silver and copper, the added weight the same (125 kg) of Palladium instead of copper and silver, we got k White Gold 21.
And for a kilo of 18 carat gold mix Le of pure gold with 250 kg of silver and copper, then we add the same weight (250 g) of Palladium instead of silver or copper got us k White Gold 18 in. .. And so on.
The information bulletin issued by the Ministry of petroleum and minerals in Saudi Arabia – Ministry of mineral resources, on 22/3/1410 minerals in the Kingdom (gold):
"Gold is a mixture of gold with Palladium, 12% or 15% nickel, and gold color tends to pink by mixing with 5% silver and 20% copper, color green italic results from mixing 75% gold, 25% silver or zinc + cadmium. The color blue if tilted mixing gold with little iron, if mixing gold with 20% aluminium, the resulting color is purple, and can control the degree of redness gold by lifting or lowering the proportion of copper added "ended.
Said Dr. Mamdouh Abdel Ghafur Hassan in his book "the Kingdom of minerals": "pure gold, not solid enough for the jewelry industry, but mixed with copper or silver or nickel or Platinum to increase its hardness and, at the same time impart distinct colors, the little brass lends it redder in color, either silver, they give it a tinge of whiteness, either increase the proportion to 25% Platinum or nickel to 15% it produces alloy called (white gold)" ended.