Comparative Qualities of Precious Metals at KJD:
Alloy	Composition	Specific Gravity	Melting Temp	Color	Vicker's Hardness
950 Platinum	95% Pt, 5% Ru	21.45	3235˚ F	light cool gray	130
950 Palladium	95% Pd	11.84	2500˚ F	light cool gray	115
14k pd white gold	58.5% Au, +Pd	13.7	2030˚ F	medium gray	150
14k precise white gold	58.5% Au, +Ni		1780˚ F	light gray
18k yellow gold	75% Au	15.6	1580˚ F	rich yellow	125
18k rose gold	75% Au, +Cu	15.5	1630˚ F	copper	195
14k rose gold	58.5% Au, +Cu	13.4	1715˚ F	copper	125
10k green gold	41.6% Au, +Ag	11.7	1480˚ F	light green yellow	170
Sterling Silver	92.5% Ag, 7.5% Cu	10.36	1640˚ F	white	75
Platinum Sterling	92.5% Ag, 3.5% Pt, +	10.6	1740˚ F	white	75
Cobalt Chrome	67% Co, 27% Cr, and 6% Mo			medium gray
316L Stainless Steel	60% Fe, 18% Cr, 14% Ni			medium gray
Titanium	100% Ti	4.5	3272	medium-dark gray

Alloy

An alloy is a combination of different metals that are melted and blended together to create a new homogenous metal with a uniform color and a new melting temperature (different from the parent metals). New alloys are created to achieve more desireable properties such as hardness and ductility.

Karat Gold

Pure, 100% fine gold is 24 karat. This is a rich, deep golden color that has been used for jewelry historically but is too soft for general purpose jewelry. Here are a few notes about "karat gold":

• 18 karat gold means that the metal is 18 parts out of 24 pure gold, or in other words, 75% pure gold. The other 6 parts (25%) consists of an alloy of other metals. 18 karat gold is the standard for European jewelry.
• 14 karat gold is 14 parts gold, or 58.5% pure gold. It is the standard for American jewelry.
• In addition to the proportion of pure gold, the term "karat" is used to signify solid gold alloys versus gold platings or gold-filled pieces of jewelry.
• Interestingly, each country has a minimum "karatage" for gold alloys that may be legally sold as gold. In the United Sates, the minimum is 10 karat gold. In France and Italy, for example, the minimum is 18 karat gold.

Colored Gold

The color of gold is created by the combination of pure gold and the other metals that it is alloyed with, or additional metal that it is mixed with. The lower the karat of colored gold, the higher the contrast of color. Black hills gold is typically 10 karat gold, or approximately 42% gold and 58% other metal. Here are a few examples of the gold alloys we typically work with along with color assessments:

• 18 karat yellow gold - rich yellow color
  
• 18 karat rose gold - true rose color - is 18 parts (75%) pure gold and the rest is mostly copper. Finicky metal that is not good for jewelry that requires torch work.
• 14 karat rose gold - true rose color - is 14 parts fine gold and 10 parts copper and silver. It is the rich red copper combined with fine gold that creates a warm rosy tone.
  
• 14 karat palladium white gold - warm, medium brownish gray color is 14 parts gold and 10 parts of an alloy that consists partly of palladium. This is a nickel free alloy.
• 14 karat high palladium white gold - cool, medium darker gray color is 14 parts gold and 10 parts of an alloy that consists mostly of palladium. This is a nickel free alloy.
• 14 karat precise white gold - light, slightly warm gray color - 14 parts pure gold and 10 parts of an alloy of nickel and other metals.
  
• 10 karat green gold - very pale yellowish sage color - is 10 parts pure gold and 14 parts of a mixture containing primarily silver.

Mokume-gane

Mokume Gane is a technique of Japanese origin in which layers of alternating colors of precious metals are fused, forged and patterned to create swirling images of color in a sheet of metal. Mokume (wood eye) Gane (metal) is derived from the ancient Japanese sword making technique wherein layers of mild steel and carbon steel were forged together to create blades of great strength and durability. A fine woodgrain pattern on a blade is the tell-tale sign of Damascus steel.

The first recorded use of mokume gane was by Denbei Shoami (1651-1728) who lived and worked in Japan. Shoami adapted the principles of forge-welded Damascus steel to create mokume gane. Advanced sword-making techniques used in Japan at the time were pivotal in the development of mokume gane, because the art of sword making was so accomplished that it directly influenced all forms of metalwork. The importance placed on swords in feudal Japan and the influence of sword-makers on Japanese art and technology is not unlike the leading role the aerospace industry has in driving the technological advances today. Swords were considered highly utilitarian and highly decorative, and the finest artists and metalworkers of the day worked side by side to create swords of great beauty and remarkable functionality. Master-apprentice relationships allowed for extensive knowledge of metallurgy to be passed down and expanded. Materials were readily available, and colored metal alloys were already in use at the time.

To achieve a successful lamination of a mokume billet using the original process required a highly skilled smith with a great deal of experience. The traditional materials used were relatively soft precious metals and alloys - gold, copper, silver, shakudo, shibuichi, and kuromido - which would form liquid phase diffusion bonds with one another without completely melting. After the metal sheets were stacked and carefully heated, the solid billet of simple stripes could be forged and carved to increase the pattern's complexity.

The modernized process typically uses a controlled atmosphere in a controlled, high-temperature furnace. Mechanical aids such as a hydraulic press or torque plates (bolted clamps) are also commonly used to apply compressive force on the billet during lamination and provide for the development of lower temperature solid-state diffusion between the layers.

Contemporary metalsmiths have rediscovered mokume gane as an expressive material with a subtle palette of precious metal colors. Due to the labor-intensive nature of fine mokume jewelry, it will remain an uncommon jewelry technique, avoiding association with mass-produced commercial jewelry.

Lisa Krikawa is an award-winning mokume gane artist, and is recognized world wide as one of the leading mokume ring makers. With clients from Australia through the U.K. to Canada and all across the 50 United States, Krikawa has quite singularly nailed the mokume-gane bridal market with her client-inspired, co-created, one-of-a-kind masterpieces.

References:

Pijanowski, H.S. and Pijanowski, G.M. (2001) Wood Grained Metal: Mokume-Gane, http://www.silversmithing.com/1mokume.htm

Binnion, J.E. and Chaix, B. (2002) Old Process, New Technology: Modern Mokume Gane http://www.mokume-gane.com/Papers/SantaFePaper.pdf

Midget, Steve (2000) Mokume Gane: A Comprehensive Study. North Carolina: Earthshine Press

Please see our Wedding Bands page for a sampling of the types of mokume-gane we use.

Shakudo

Shakudo is a Japanese alloy made of 96% copper and 4% fine gold. It has a natural dark patina and, if worn away by sand or chemicals, it will naturally re-darken through contact with water, air, the skin, and chemicals such as ammonia. While this alloy is currently found in some mokume rings, it is an unstable metal, and is not recommended to be worn in contact with the skin. The natural salts in the skin can etch away the metal over time.

White Gold

White gold is pure gold that has been alloyed with nickel and/or palladium and other metals to acheive a "whiteness" of the metal. White gold is a gray metal with a wam hue when alloyed with nickel (ring D). This metal can be brittle and problematic when setting stones or resizing rings. When 14k white gold is alloyed with palladium, it is nickle-free (great for people with sensitivities) but it is a warm, light brown color (ring B). For a slightly darker, cooler gray hue, 14k white gold can be alloyed with a high percentage of palladium (ring C); however, this makes for a softer metal. Commercial white gold jewelry is commonly nickle based and rhodium plated (see below). Our standard white gold is 14k palladium white gold (B). It is not brittle, works well for setting stones, is nickle-free, and is highly unlikely to crack during sizing operations. We rhodium plate only upon request.

Rhodium Plating of White Gold

Most commerical white gold jewelry is plated with rhodium, a platinum group metal with a
bright white color. White gold is warmer and darker than the rhodium, so as it wears the rhodium scratches off, showing the darker color underneath. Sometimes the white gold under the plating is slightly to very yellowish in color. We do not typically rhodium plate our jewelry. We can rhodium plate if the bright white color is desired, however, we prefer to use palladium to white gold.

Platinum

Why choose platinum? Platinum is considered to be the "most precious" of the precious metals. Platinum is your metal of choice, when only the best will do. Rarer than gold, stronger and more enduring - platinum is also the choice of jewelry designers for fine heirloom quality jewelry. Platinum is always a cold light gray, and will retain its polish longer. Also, platinum does not wear down as gold does, so, over the course of a lifetime, it will remain virtually the same weight and size. It is much better to set stones in platinum for that reason.

Platinum History

Platinum evokes the future through the cool gray color and technological uses, but it also recalls the past. In the 1890's the world renowned Louis Cartier introduced the metal as a setting, and made it part of his most exquisite creations for kings and millionaires. During the first 40 years of the twentieth century, platinum was the preferred metal for wedding and engagement rings and was almost always used to enhance the beauty of diamonds and other gemstones. However, for the duration of World War II, platinum was declared a strategic material and its use in most non-military applications was prohibited.

Platinum Statistics

Platinum is quite simply the ultimate in precious metals.

• Platinum jewelry’s purity is generally at the 90 to 95% level and it is usually alloyed with other rare platinum group metals. This means you are getting more of the precious metal you are paying for and avoiding low value base metals that are commonly used in gold alloys.

• Platinum is 30 times more rare than gold.

• Platinum is durable. All precious metals will scratch, however, when platinum scratches it tends to displace rather than lose metal weight. This means your platinum jewelry will outlast other precious metal jewelry and hold stones in place more securely.
  

• Platinum is naturally white and will not tarnish. White gold is achieved by “bleaching” yellow gold with other elements such as nickel and palladium. This process of whitening is not durable and thus yellowing and repeated rhodium plating are key disadvantages of white gold alloys.

• Platinum is one of the densest elements on earth, only exceeded by osmium and iridium — two other platinum group metals. One cubic foot weighs around 1,330 pounds. This translates into a very rich and weighty feel in jewelry pieces that can only be experienced with platinum.

• Due to the unusual characteristics of this metal, a platinumsmith must have a different set of tools than a goldsmith. For instance, platinum melts at 3225 degrees fahrenheit, compared to fine gold which melts at 1945.

Palladium

Palladium is the new kid on the block and has a lot to offer as a vastly superior alternative to white gold. Palladium can best be described as a sister metal to platinum and has the following key characteristics:

• Palladium is naturally white and will not tarnish. Like platinum, palladium does not require rhodium plating and will maintain its bright white color indefinitely. In contrast, white gold will yellow over time and require repeated rhodium plating to maintain its whiteness.

• Palladium is 30 times more rare than gold.

• Palladium is lighter than platinum. Palladium’s density is roughly half that of platinum, making it ideal for earrings, necklaces, and pendants that might otherwise be too heavy in platinum. In addition, for those that cannot afford platinum, the lighter weight and lower metal price makes for an affordable yet very high quality piece of jewelry.

• Palladium rarely causes allergic reactions. Many people who are unable to wear white gold alloys due to the wide use of nickel as an alloying element will find palladium to be a great alternative.

• Palladium is durable. In a study conducted by Hoover and Strong, after simulated wear tests TruPd™ 950 palladium had a 15% greater wear resistance over 14k white gold. For comparison, under identical test conditions 950 Platinum had a 23% greater wear resistance over 14k white gold.

• HISTORY: When World War II began, the British government declared Platinum a strategic metal and its use in non-military applications, including jewelry, was disallowed. As a result, Palladium made its first appearance in jewelry in 1939. The demand for wedding bands increased during the early 1940's and many were made of Palladium.
  

Sterling Silver and Krikawa-Sterling

Sterling Silver is the whitest of all the metals, and thus a great metal to use in mokume, as the white color provides the best contrast with other colored metals. To be marked "Sterling" it must be 925 parts silver (or 92.5%). It is traditionally alloyed with 7.5% copper. Krikawa-sterling is still 92.5% silver, however, the alloy contains palladium, which makes Krikawa-Sterling a superior sterling. It is tarnish resistant and has better wearability. Krikawa Jewelry Designs uses Krikawa-Sterling in our mokume. Fine silver (99.9% silver) is generally too soft for most jewelry applications.

Cobalt Chrome

• Cobalt-Chrome is an alloy composed of approximately 67% Cobalt, 27% Chromium, and 6% Molybdenum. Renowned in the metals industry for its superb wear resistance, Cobalt Chrome is the metal of choice for artificial joints including knees, hips, fingers, toes, and others. As such, the metal is highly biocompatible and ideal for use in certain jewelry applications as well.

• While Cobalt-Chrome has an incredible luster after high polish, it does, however, have certain limitations in jewelry making. The high level of wear resistance also causes it to resist tools, making it very difficult to drill holes, set stones, or size in a traditional manner. The best use for this metal can therefore be found in pendants, earrings cufflinks, necklaces and bracelets etc. that do not require sizing and designs that showcase the metal versus stones. Stones, when needed, can be riveted or glued in place. Another benefit of Cobalt-Chrome is its susceptibility to blackening. Blackening is done through a chemical process that creates a black oxide layer providing a wonderful contrast with platinum, palladium and gold alloys. 

• We do not recommend using metals with this kind of hardness for rings. We are willing to consider creating some designs with this metal, however we do require a release to be signed indicating that the buyer understands that in case of a medical emergency, most medical service personel DO NOT have the equipment required to cut this ring off.

316L Stainless Steel

• 316 Stainless is the workhorse alloy for the jewelry industry’s stainless needs. It is composed of approximately 60% Iron, 18% Chromium, and 14% Nickel with small percentages of Molybdenum, Manganese, and others. Despite the fact that 316L has 14% Nickel, it is still considered among the most biocompatible of the stainless series. It has been used in the medical industry for heart stents and spinal implants, among others. Nevertheless, it is important to be aware of the risk for nickel sensitivity when using this alloy for jewelry applications. This is particularly true for piercing designs where, ironically, it is the most popular.

• Other benefits of 316L are its rust resistance and malleability—both key factors for jewelry use. Stones can be set with relative ease and rust is better inhibited by the specific combination of elements used in 316L versus other stainless steels.

Titanium

Titanium is an extremely lightweight and hard metal. It is becoming very popular for use in jewelry, but was originally found in the aerospace industry. It has a medium-dark gray color. We do not make rings out of titanium.