Because of the softness of pure (24k) gold, usually alloyed with base metals for use in jewelry, altering its hardness and ductility, melting point, color and other properties. Alloys with lower caratage, typically 22k, 18k, 14k or 10k, contain higher percentages of copper, or other base metals or silver or palladium in the alloy. Copper is the most commonly used base metal, yielding a redder color. Eighteen-carat gold containing 25% copper is in antique and Russian jeweler. It has a distinct, though not dominant, copper cast, creating rose gold. Fourteen-carat gold-copper alloy is nearly identical in color to certain bronze alloys, and both used to produce police and other badges. Blue gold can be made by alloying with iron and purple gold can be made by alloying with aluminum, although rarely done except in specialize jewelry. Blue gold is more brittle and therefore more difficult to work with when making jewelry. Fourteen and eighteen carat gold alloys with silver alone appear greenish-yellow and referred to as green gold. White gold alloys made with palladium or nickel. White 18 carat gold containing 17.3% nickel, 5.5% zinc and 2.2% copper is silver in appearance. Nickel is toxic, however, and its release from nickel white gold controlled by legislation in Europe. Alternative white gold alloys are available based on palladium, silver and other white metals (World Gold Council), but the palladium alloys are more expensive than those using nickel. High-carat white gold alloys are far more resistant to corrosion than are either pure silver or sterling silver. The Japanese craft of Mokume-gane exploits the color contrasts between laminated colored gold alloys to produce decorative wood-grain effects.

Law Firm

A law firm is a business entity formed by one or more lawyers to engage in the practice of law. The primary service rendered by a law firm is to advise client’s individuals or corporations about their legal rights and responsibilities, and to represent clients in civil or criminal cases, business transactions, and other matters in which legal advice and other assistance are sought.

In many countries, including the United States and the United Kingdom, there is a rule that only lawyers may have an ownership interest in, or be managers of, a law firm. Thus, law firms cannot quickly raise capital through initial public offerings on the stock market, like most corporations. In the United States this rule is promulgated by the American Bar Association and is adhered to in all U.S. jurisdictions, except the District of Columbia. The U.K. has a similar rule, but in recent years law firms have been able to take on a limited number of non-lawyer partners.

The rule was created in order to prevent conflicts of interest. In the adversarial system of justice, a lawyer has a duty to be a zealous and loyal advocate on behalf of the client, and also has a duty to not bill the client unreasonably. Also, as an officer of the court, a lawyer has a duty to be honest and to not file frivolous cases or raise frivolous defenses. A lawyer working as a shareholder-employee of a publicly traded law firm would be strongly tempted to evaluate decisions in terms of their effect on the stock price and the shareholders, which would directly conflict with the lawyer's duties to the client and to the courts.

Law firms are typically organized around partners, who are joint owners and business directors of the legal operation; associates, who are employees of the firm with the prospect of becoming partners; and a variety of staff employees, providing paralegal, clerical, and other support services. An associate may have to wait as long as 9 years before the decision is made as to whether the associate "makes partner." Many law firms have an "up or out policy" pioneered around 1900 by partner Paul Cravath of Cravath, Swaine & Moore: associates who do not make partner are required to resign and join another firm, go it alone as a solo practitioner, go to work in-house in a corporate legal department, or change professions burnout rates are very high in law.

Making partner is very prestigious at large or midsized firms, due to the competition that naturally results from higher associate-to-partner ratios. Such firms may take out advertisements in legal newspapers to announce who has made partner. Traditionally, partners shared directly in the profits of the firm, after paying salaried employees, the landlord, and the usual costs of furniture, office supplies, and books for the law library or a database subscription. Partners in a limited liability partnership can largely operate autonomously with regard to cultivating new business and servicing existing clients within their book of business. However, many large law firms have moved to a two-tiered partnership model, with equity and non-equity partners. Equity partners are considered to have ownership stakes in the firm, and share in the profits and losses of the firm. Non-equity partners are generally paid a fixed salary albeit much higher than associates, and they are often granted certain limited voting rights with respect to firm operations. The oldest continuing partnership in the United States is that of Cadwalader, Wickersham & Taft, founded in 1792 in New York City.