The Elements of Jewelry
Stroll by a jewelry store on any day, and you’ll see cases full of shiny items. Light glints off of gold rings, and silver necklaces sparkle against velvet backgrounds. The jeweler who owns the shop and makes the jewelry has to consider both beauty and science. Someone who earns their living by making beautiful things has to know a lot more than you might think. A jeweler makes beautiful rings, bracelets, and necklaces, but he or she also must know about many different stones and metals. Before a ring ever slips onto a finger, before a necklace ever drapes a neck, a series of decisions must be made about everything regarding the jewelry.
Jewelry is made of metals and stones with different characteristics. Every material in the world has its own properties, and a jeweler must know the characteristics of the materials he or she works with inside and out. By understanding the properties of metals and stones, the jeweler knows how they react, mix, melt, and hold up to everyday use. Jewelers sometimes blend metals themselves, but they often purchase metals blended by goldsmiths and forgers. As these workers shape and form the metal combinations, they begin to create the jewelry people wear.
Gold and silver are two of the most common metals used for jewelry, but they are very different if you compare them. Scientists know gold by its chemical symbol Au. Gold is a soft but dense metal. It is malleable, which means it can be shaped. It can be hammered out into thin sheets, it can be ground into a thin powder, and it becomes liquid when heated. It can also conduct electricity. Gold has a bright yellow color and luster that does not tarnish in air or water. A jeweler knows all of the properties of gold and can identify it based on these characteristics.
Because gold is soft, it needs other metals to support it so that it can stand up to the normal wear-and-tear of life when worn as jewelry. It must be able to endure hand-washing, sweating, and being worn while working. So if pure gold is used in a ring, it will be very soft and might wear away, scratch, or dull over time. For this reason, pure gold is combined with other metals to form alloys used in jewelry.
Silver is less valuable than gold. It is also slightly harder. Scientists refer to silver with the symbol Ag. Silver has the best ability to conduct electricity of any element. It can exist in pure form, or combined with other metals as an alloy. Silver shines brightly when polished. Since ancient times, it has been used as a precious metal to make coins, ornaments, and silverware. A buyer might choose silver instead of gold because of its price and durability.
Although gold and silver have captivated the minds of adventurers and conquerors, there is another metal that is actually even more valuable: platinum. Scientists use the symbol Pt to represent it. It is silver-white in color, lustrous, and malleable, although not as malleable as gold. Its strength makes it resistant to wear and tarnish, and it does not easily corrode or wear away. Platinum makes strong and lasting jewelry, and jewelers prize it for that.
In addition, platinum is not very likely to create a skin reaction. Sometimes, jewelry can react to sweat on the skin. A green band can appear on the skin underneath a ring or bracelet where the metal rubs it. This happens when metals mixed with gold react to the acidity in sweat on the skin. That reaction makes the metal corrode, which forms a salt compound that gets absorbed into the skin and turns it green in patches. The higher the percentage of gold in jewelry, the higher the quality, and the less likely it is to create the green-skin effect.
Before jewelers and other workers transform metals into liquid and shape them, they understand what temperatures the metals must be subjected to in order to melt. Because metals are chemical elements, their melting points are predictable. Silver turns to liquid at 1763.2 degrees Fahrenheit. Gold will always melt at 1947.5 degrees Fahrenheit, and platinum always melts at a much higher temperature of 3214.9 degrees Fahrenheit. If jewelers or scientists aren’t sure what type of metal something is, they can subject it to high temperatures and determine its identity based on the minimum temperature needed to melt it.
What happens when a metal is melted? When a metal goes from solid to liquid, the change of state means the molecules change their behavior. Imagine that a solid piece of gold has molecules that are closely spaced and vibrate in position, but don’t change their position in relation to other molecules. As temperatures rise and the state of gold changes to liquid, the molecules begin to move to other positions. They are in constant contact with one other.
Jewelers and goldsmiths are not the only people who make decisions about jewelry. The jewelry business employs many people who work with and assess precious metals and stones. Gemologists analyze the characteristics of gemstones and then certify their quality. They use microscopes and other tools to examine gemstones to check for purity and strength. Then, they write reports and documents that certify the quality of these items. There are also jewelry appraisers who carefully examine jewels and assess their value for pawnbrokers, jewelry stores, and insurance companies. Like jewelers, both appraisers and gemologists must understand the properties of the stones and metals they see every day.
characteristic char ·ac ·ter ·is ·tic
- indicating the typical or distinguishing attributes and qualities of a person, group, action, or thing.
This pattern of color is characteristic of this type of bird.
Crying is characteristic behavior of infants.
- marked by uniqueness or distinctiveness.
His characteristic way of walking makes him easy to recognize.
- a salient feature; distinctive trait.
Tails that can grasp things are a characteristic of monkeys.
característica: The Spanish word característica means characteristic.
These are some examples of how the word or forms of the word are used:
- Everyone has traits: characteristics and qualities that make us who we are.
- Though humpback whales look similar to fish and share many characteristics, they are, in fact, mammals. Instead of scales, they are covered in skin.
- Slight chemical changes can radically modify the characteristics of a compound, and we don’t have to look to radically different elements to find enormous differences. Sometimes only a small difference in chemical composition results in a very important alteration.
- According to some butterfly experts, there are approximately 20,000 kinds of butterflies in the world. Each species (or type) of butterfly has its own genetic information that dictates what characteristics it will have and distinguishes it from other butterflies.
- Charles Darwin outlined the idea of natural selection in his 1859 book, On the Origin of Species, where he explained there are certain characteristics that help an animal survive, such as a sharp beak that allows birds in the Galapagos Islands to better find and eat their food.
- When making the robot, the researchers will have to look through all of the ideas they’ve created in their computer program, and pick and choose which characteristics will work best together to create a robot that can easily take out the garbage.
- Bats use sonar to hunt insects at night. Some lizards have tails that break off and regrow in a few months. The wings of certain nonpoisonous butterflies look exactly like those of their poisonous relatives. All these strange characteristics are the result of one important biological trait: adaptation.
- They spoke with heavy accents and brought over a very different style of clothing than what most Americans wore in those days. These characteristics, and the fact that many of them were uneducated and untrained in any trade or business, made their new neighbors and countrymen scorn them.
combination com ·bi ·na ·tion
- things that are brought together or combined.
The soup had a combination of chicken and vegetables.
- the act of combining or state of being combined.
The combination of iron with tin produces bronze.
The combination of these three paintings on this wall is very pleasing.
- the result of an act of combining; things that are combined.
The film was a combination of a Western and a comedy.
- a series of numbers used to open a lock.
Do you remember the combination to this old lock?
combinación : The Spanish word combinación means combination.
These are some examples of how the word or forms of the word are used:
- This combination of hydrogen and oxygen is simply what makes water what it is.
- Abraham was gentle and a showoff, a rare combination for an elephant, which made him the perennial crowd favorite of the show.
- She was pretty, he thought, and braver than he was, and the combination made him nervous. It also made him very glad that she was on his side.
- Humans enjoy five different types of taste: sweet, sour, salty, bitter and umami (savory or meatiness). Any other taste you can think of is made up of a combination of these.
- Jake is interested in becoming a chef someday-he often tries out new recipes on his family. Alice likes to cook, but doesn’t get as excited about new foodcombinations like her brother.
- Sexual reproduction results in genetically new offspring from the fusion of male and female sex cells. Humans reproduce sexually and their offspring are genetically a combination of their parents’ features and DNA.
- There are some chefs in this world who reject or reinterpret traditional cooking techniques and cuisines. They push the boundary of food with new techniques to create entirely new combinations of flavor and texture. They take states of matter, physical changes, and chemical changes of food to a whole different level.
- If we are playing basketball, we think about where the ball is going to go in physical space and how we can control it. If we are making a sandwich, we think about different combinations of flavors and how to make the sandwich taste as good as possible by combining those flavors. If we are deciding what to wear in the morning, we think about the visual qualities of different clothes, imagining what the most appealing combination might be.
material ma ·te ·ri ·al
- anything used for building or making new things. Wood, metal, paint, and paper are examples of materials.
They delivered the building materials to the construction site.
I have to buy materials for my art class.
Karin bought some material for a new dress.
- anything used for constructing or making something else.
Materials such as limestone, marble, and glass were used in vast amounts to build the cathedral.
A lot of the material purchased for the construction project was never used.
- cloth or fabric.
She’s bought all the material to make her wedding dress.
- any group of ideas, sources, data, or the like that can be used to create a larger work.
She gathered material for her novel by reading newspapers from the 1920s.
- important or relevant.
The constant presence of loved ones made a material difference in the patient’s recovery.
- of or pertaining to the physical or tangible.
A priest must be concerned with both the material and the spiritual realms in order to be of service.
- in law, relevant to the issues of a case.
The witness held back information that was material to the case.
material: The Spanish word material means material.
These are some examples of how the word or forms of the word are used:
- Chlorine is a toxic gas that is extremely harmful to the respiratory system and may also react with certain flammable materials.
- We can identify materials according to a variety of properties. Scientists have determined several different measurements to help label materials. Some examples are temperature, hardness, color and length.
- The food of almost any kind of animal can be traced back to plants. This is obvious in animals that are herbivores, since they survive by eating plant material.
- Until the 8th century, paper was only produced in China and other parts of Eastern Asia. Scholars in Europe, the Middle East and Africa had to make do with papyrus, a brittle material made only in Egypt; or parchment, a very fine sheet made from the skin of animals.
- After a solution or a set of testable solutions have been developed, the next step is to test them rigorously and systematically so that no aspect goes unexamined. In a controlled experiment, different groups of testable material are subjected to testing and compared with a control group for which outcomes are known. Experiments are usually regarded with a measure of skepticism themselves and are subject to change and redesign as the testing stage continues.
- Wind power uses a machine called a turbine that turns the energy of the wind into electricity. Coal, oil, and gas power burn different kinds of material, creating heat that gets turned into electricity. Solar power generates electricity from the sun’s light-although not as easily as a plant.
- This means that an inmate may go many years with limited access to reading material. For a person who loves books or who wishes to learn about the world, this can be a harsh sentence indeed.
- You can pierce your nose, get a tattoo, dye your hair, shave your head, get your kidneys removed, put on a silly hat-it doesn’t matter how much you alter your body during your lifetime. None of those things will translate into genetic material to be passed down to the next generation.
- Truss bridges, however, feature loadbearing structures called trusses, which are connected elements forming triangles. These are one of the oldest types of modern bridges, and are one of the cheapest to make, since they often require less material than other bridges.
- When two organisms-in this case, those organisms would be Alice and Jake’s parents: Pete and Rachel-create a third organism through reproduction, many variables come into play. It’s a complex lottery in which offspring of the first two organisms inherits a combination of their genetic material.
ReadWorks.org · © 2014 ReadWorks®, Inc. All rights reserved.
Phụ huynh và học viên có thể xem đáp án và download file PDF tại đây