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Category: Learn Minerals, Rocks and Crystalz

  • Uses of Cinnabar

    Cinnabar is the only important ore of mercury. For thousands of years, cinnabar has been mined and heated in a furnace. The mercury escapes as a vapor that can be condensed into liquid mercury. People began using cinnabar for pigments thousands of years ago in Italy, Greece, Spain, Japan, China, Turkey, and the Mayan countries of South America. Through time, people in…

  • Metacinnabar

    Metacinnabar is a polymorph of cinnabar. It has the same chemical composition (HgS) as cinnabar but a different crystal structure. Cinnabar is trigonal, while metacinnabar is isometric. The two minerals should not be confused with one another because metacinnabar has a metallic gray color, a gray-to-black streak and a metallic-to-submetallic luster.

  • Properties of Cinnabar

    The most striking property of cinnabar is its red color. Its bright color makes it easy to spot in the field and is a fascination for those who discover it. It has a Mohs hardness of 2 to 2.5 and is very easily ground into a very fine powder. It has a specific gravity of 8.1, which…

  • Cinnabar is Toxic

    As a mineral ore of mercury, cinnabar is a hazardous material. It should be treated as a toxic substance. It is not a mineral to be handled or used with students. It should be stored with a label that warns unknowing people who might encounter it in your specimen cabinet, display case, or storage location.

  • Geologic Occurrence of Cinnabar

    Cinnabar is a hydrothermal mineral that precipitates from ascending hot waters and vapors as they move through fractured rocks. It forms at shallow depths where temperatures are less than about 200 degrees Celsius. It usually forms in rocks surrounding geologically recent volcanic activity but can also form near hot springs and fumaroles. Cinnabar precipitates as coatings…

  • What is Cinnabar?

    Cinnabar is a toxic mercury sulfide mineral with a chemical composition of HgS. It is the only important ore of mercury. It has a bright red color that has caused people to use it as a pigment, and carve it into jewelry and ornaments for thousands of years in many parts of the world. Because it is toxic,…

  • Burying the Coal Formation Idea

    The most convincing evidence that coal did not play a role in the formation of most diamonds is a comparison between the age of Earth’s diamonds and the age of the earliest land plants. Most of the rock-hosted diamond deposits that have been found were formed during the Precambrian Eon – the span of time between Earth’s…

  • Formation on Earth’s Surface

    In the 1950s, new methods of diamond formation were discovered on Earth’s surface. Scientists were able to create the temperature and pressure conditions needed to create diamonds in a lab. Most of the early diamonds were not gem quality, but they were perfect for use as abrasive granules in drill bits, cutting tools, and grinding…

  • Formation in Space

    NASA researchers have detected large numbers of nanodiamonds in some meteorites. (Nanodiamonds are diamonds that are a few nanometers – billionths of a meter in diameter.) About three percent of the carbon in these meteorites is contained in the form of nanodiamonds. These diamonds are too small for use as gems or industrial abrasives; however, they are a…

  • Formation at Impact Sites

    Throughout its history, Earth has been repeatedly hit by large asteroids. When these asteroids strike the earth, extreme temperatures and pressures are produced. For example: when a six mile (10 kilometer) wide asteroid strikes the earth, it can be traveling at up to 9 to 12 miles per second (15 to 20 kilometers per second). Upon…