About multi-colored golds (and a few other things)
Color (and metals):
Pure gold, 24K*, is always a deep orange yellow color . When other metals are added to pure gold the color changes (so does the hardness). As a general rule, adding copper makes a gold reddish, silver makes it greenish-yellow, nickel or palladium makes it white. Exotic colors like purple, blue, and teal are made with other metals e.g., aluminum makes a purple gold. Exotic colored golds usually have very poor mechanical properties that may preclude their use in rings (except as accents); we think of them as rather fragile "precious stones", better used as parts of pendants, brooches, etc. Many other metals, and other elements, are added in small quantities to change the mechanical properties, but their influence on color usually isn't significant. Unlike some jewelers, we do not electroplate our rings to achieve a color of gold—the color you see is goes entirely through that piece of gold.
Pure platinum and platinum alloys used in jewelry are always white . The white is usually a bit cooler than white gold alloys.
We also use many other metals to create the richness of design we want: mild steel, titanium, copper and its alloys, niobium, zirconium, tungsten…. It's not exactly a Crayola™ box of colors, but the range is far wide.
* "K", karat, is a measure of gold purity—24K is 100% pure gold. 18K gold is 75% pure gold (18 divided by 24). Just as a note, "Ct.", carat, is a measure of stone weight: 5 Cts. = 1 Gram.
Very few people, if any, are allergic to pure gold. What they may be allergic to are some of the metals used in making gold alloys. The most common is to nickel which is mainly used in making white gold. If you know you are allergic to a specific metal/s please inform us so we can advise you on alloys to avoid. In over 20 years of business, we have seen very few true metal allergies, in most cases the ring was simply too tight, and it's trapped soap or detergent that causes the skin irritation. Please consult your physician if you have any doubts about an allergy.
Colors on monitors:
Finally, the color you see on your monitor may not be the exact color of the gold (or stone)—monitors differ slightly in how colors are rendered. Feel free to contact us if you have any questions [AAP].
Because each ring is hand-made, ring widths or thicknesses are usually accurate to ± 0.2mm. Stones are weighed to an accuracy of ± 0.01 ct. (large semi-precious stones are often described in terms millimeter size not weight).