Rocks & Minerals

Jade is the name of a gemstone that consists of jadeite, nephrite or both. Jadeite is rarer than nephrite. Imperial jade refers to jadeite that has a translucent emerald green color.

Tanzanite is a gemstone that is only found in the foothills of Mt. Kilimanjaro. Many different shades of tanzanite include brown, iridescent blue, violet, gray and green. Tanzanite can be a good...

Gemologists are able to identify gems such as diamonds, rubies and sapphires to find out if a stone is genuine or synthetic. Identifying gems involves observing and testing them for their...

One of the most popular gemstones, the amethyst crystal is highly prized for its rich purple color and has been used in a variety of ways for thousands of years.

A moonstone is a lovely gem that is often quite affordable. It really depends on your budget for the moonstone jewelry. You can find moonstone rings, moonstone bracelets and so forth. Moonstone is...

Because of its vivid, opaque color, with hues from green to sky blue, turquoise has been a valued gem in many cultures, from the ancient Egyptians to the Aztecs and Native Americans. The...

The aquamarine is one of the birthstones of March and has long had an association with the sea. The name comes from the Latin "aqua" and "marina," which mean water and sea---a reference to the...

Determining the value of gems is a combination of cut, caret, color and clarity. In comparing emeralds versus rubies, the two precious stones both have examples of rare gems, typically of a large...

The amethyst, classified as a semi-precious gemstone, is the birthstone of February and is seen in jewelry dating back many hundreds of years. Amethyst is a gemstone with an interesting...

A pink diamond is one of the rarest and most expensive colors of diamond. It is considered a fancy diamond, and is found in a range of colors, from light to dark pink and is graded on a color scale.

Natural gemstones, when mined, are not always as colorful as they appear in a jeweler's case or shop. In order to bring about the intensity of a gemstone's color, enhancements need to be made....

A streak test is one tool that geologists use to determine the identity of a mineral. The “streak” is the color of the mineral in powdered form. Some minerals will have a streak color that is...

Sapphires are made of corundum, an aluminum oxide. Corundum is the second hardest natural material, second only to diamonds. It forms in igneous rock (cooled magma) or metamorphic rock (rock...

The ruby is a precious gemstone, the value of which is determined by its color. It is the birthstone for people born during July. Rubies are also linked to the Zodiac sign Capricorn and are the...

Opals are one of the five gemstones, along with diamond, emerald, ruby and sapphire. Gemstones are minerals; in the case of opal, that mineral is silica. Chemically, opal is silicon dioxide plus...

Obsidian is a naturally occurring glass formed as igneous rock. It was originally molten lava but cooled so quickly no crystals formed. The lack of crystalline structure means that obsidian in not...

There are many types of minerals, with several bearing a strikingly similar appearance to each other. Some minerals have a higher market value than others based on a certain set of...