History of Gold Bullion / Culture / Sustainability
MATERIALITY
Gold and copper are the only non-ferrous metals. Gold can be alloyed with other metals to produce a range of colors, which makes it especially popular in jewelry. In addition to its versatility in color, gold is also known for its exceptional chemical properties. Its malleability allows for the creation of ultra-thin gold leaf and fine gold wires used in electronic components. Jewelry designs that take advantage of these unique properties are continually being researched and developed.
Gold is highly resistant to chemical reactions, remaining unaffected by most substances except aqua regia", a mixture of nitric and hydrochloric acids capable of dissolving it.
Gold is renowned for its exceptional malleability*1. For instance, just 1 gram of gold can be stretched into a wire approximately 3,000 meters long or hammered into ultra-thin gold leaf. These properties make it ideal for intricate applications, such as jewelry crafting—a tradition that has been practiced for centuries. However, because pure gold (24K) is quite soft, most jewelry is crafted using harder gold alloys, such as 18K or 14K, to enhance durability.
色展開のしやすさ
金合金は割金*の素材や割合で色のバリエーションを自在に作ることが可能です。
Color Variety
Gold alloys can easily be made in different colors by altering the types and amounts of metals used.
Gold is exceptionally dense, with a specific gravity of 19.32-one of the highest among metals-resulting in its characteristic heavy and solid feel.
金
Gold
19.32
銀
Silver
10.49
銅
Copper
8.93
鉄
Iron
7.87
比重(g/c㎥)
注釈一覧
Annotations
*1 展延性(Malleability): 物質に引っ張る力を加えた際に変形する能力。(The ability to be easily changed into a new shape.)/*2 割金(Alloy): 貴金属を目的の品位にし、硬さや加工性を調整し、金においては色調を作るために添加する金属。(Metals added to precious metals to bring them to the desired grade, to adjust their hardness and workability. In the case of gold, alloys are added to create a range of colour tone.)/*3 王水(Aqua regia): 塩酸と硝酸1:3の混合液、強力な酸化溶解性を持ち、通常の酸では溶けない金、白金などの貴金属を溶解する。(Aqua regia is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. It has strong periodical in solubility and dissolves gold, platinum and other precious metals that cannot be dissolved by normal acids.)