Gemstones and Metals

______ are scientists who study minerals and have many ways of identifying them.

• Geologists

• Mineralogists

• Biologists

• Chemists

Of the more than 2,000 identified minerals that God created, 100 of them are considered very hard, rare, beautiful minerals called (a)   . Once they have been cut and polished, the minerals are then called (b)   .

• gemstones

• gems

• rubies

🔶 (a)   are crystals of carbon formed under tremendous heat and pressure. They're the hardest of all substances and can cut through metal, glass, and other stones and can only be cut themselves with another gemstone of their kind.

🔶 (b)   are one of the most widely distributed minerals, and their impurities give them a wide range of colors. They can be found as large, colorless, six-sided, prism-like crystals or as rocks containing microscopic crystals.

🔶 (c)   are the rarest gemstones and get their beauty from their color and luster. Most today are synthetic (man-made), which have been throughout most of the 20th century.

• Diamonds

• Quartz

• Rubies

Tags

NGSS.MS-PS1-3

Match the following uses for each gemstone.

• Rubies

• Used for industrial use in lasers, such as surgery, carrying messages in telephone systems or cutting and shaping metals

• Quartz

• One of the most widely distributed minerals; Can carry an electric current and can be used to channel electricity to produce signals for radio, TV, and radar

• Diamond

• Used for jewelry, but greatest value is for industrial use like cutting through metal, glass, and other stones

Match the following methods to identify rocks.

• Acid Test

• When tiny particles of minerals are burned, each mineral produces a flame of a particular color

• Cleavage

• A mineral's ability to reflect light

• Streak Test

• Identifying the true color of minerals by rubbing the rock across an unpolished porcelain tile; Soft minerals leave a streak of powder showing their true color

• Flame Test

• The way a mineral factures or breaks

• Luster

• Used to check special characterists of minerals using acid (ex: vinegar or lemon)

Answer explanation

Another method to identify a mineral is the hardness test. To test a rock, try to scratch it with an object whose hardness you know. Friedrich Mohs scale ranges from 1 (the very soft mineral talc) to 10 (the hardest mineral diamond). If you can scratch a rock with your fingernail, it has a hardness no greater than 3.

(a)   is the only metal that is liquid at room temperature.

(b)   is a radioactive metal that is the primary source of nuclear power.

(c)   is a lightweight, silvery-colored metal that can be formed into almost any shape and is rustproof.

(d)   is the best low-cost conductor available.

(e)   is the best conductor of electricity.

• Mercury

• Uranium

• Aluminum

• Copper

• Silver

• Iron

Which is our most useful metal?

• Aluminum
• Copper
• Gold
• Iron

Answer explanation

Iron is made into thousands of products, and its alloys are made into thousands more. Its easily hammered into sheets and drawn into wires., and it mixes readily with other metals and minerals to form useful alloys. It also conducts electricity and heat well and is easily magnetized.

**Iron's most common alloy is steel, which is used in the making of tools, ships, plumbing, and beams for skyscrapers.

Which is a bright yellow metal that is so soft it can be hammered into sheets?

• Copper
• Platinum
• Gold
• Silver

Answer explanation

Because gold is soft, it can be hammered into sheets called gold leaf which are so thin that light can shine through them.

Because mercury flows easily and quickly, it has the common name ______.

• silverstream

• liquid metal

• quicksilver

Answer explanation

Mercury has been used inside thermometers, barometers, and thermostats. It is poisonous to touch because it can be absorbed through the skin. Mercury also produces vapors that are poisonous if breathed in.

(a)   , a mixture of copper and zinc, and (b)   , a mixture of copper and tin, are copper alloys.

• Brass

• Bronze

• Steel

Tags

NGSS.MS-PS1-1