Mineral Identification January 24 2013

Jan 25, 2013 To start today, I must apologize for a typing error. A few weeks back I wrote: Let's review, a mineral is: Naturally occurring A solid **Is organic** (mostly with a few exceptions) SHOULD READ "In organic" Has a fixed chemical formula Has an orderly crystalline structure Jan 11th we looked at how minerals are classified and the family groups they are organized into. This is called MINERAL CLASSIFICATION. Today we look at MINERAL IDENTIFICATION. Mineralogists consider the below physical characteristics or properties to help them identify a specimen. Color: most minerals have a distinctive color that can be used for identification. Streak: the color of the mineral in powdered form. Streak shows the true color of the mineral. Because streak is a more accurate illustration of the mineral’s color, it is more reliable than just color for identification. Hardness: one of the better properties to use for identifying a mineral. Hardness is a measure of the mineral’s resistance to scratching. The Mohs scale is a set of 10 minerals whose hardness is known. The softest mineral, talc, has a Mohs scale rating of one. Diamond is the hardest mineral and has a rating of ten. 1. Talc 2. Gypsum 3. Calcite 4. Fluorite 5. Apatite 6. Orthoclase Feldspar 7. Quartz 8. Topaz 9. Corundum 10.Diamond Cleavage or Fracture: minerals tend to break along lines or smooth surfaces when hit sharply. Different minerals break in different ways showing different types of cleavage. Fracture describes the quality of the cleavage surface. Most minerals display either uneven or grainy fracture, conchoidal (curved, shell-like lines) fracture, or hackly (rough, jagged) fracture. Crystalline Structure: minerals develop through natural atomic forces that create symmetrical exterior faces of the crystal. Crystals are categorized based on the number of faces or axes it has. *Cubic has three equal axes. eg. diamond, fluorite. *Hexagonal has four axes creating a six fold symmetry. eg. emerald. *Monoclinic has three unequal axes creating an elongated shape. eg. kunzite. *Orthorhombic has three axes at 90 degrees of each other. eg. cats eye. *Tetragonal resembles two to four sided pyramids joined at the base. eg. zircon. *Triclinic the most asymmetrical shape. eg. feldspar, turquoise *Trigonal is a elongated lozenge shape. eg. tourmaline, calcite. There are also Organic or amorphous categories eg. Amber, pearl, coral. Diaphaneity or Amount of Transparency: the ability to pass light through it. Tenacity: how a mineral is held together or resists separation. Magnetism: a quality that allows a mineral to attract or repel other magnetic materials. Luster: indicates how much the surface of a mineral reflects light. Luster of a mineral is described in the following terms: Metallic: The mineral is opaque and reflects light as a metal would. Sub-metallic: The mineral is opaque and dull. The mineral is dark colored. Nonmetallic: The mineral does not reflect light like a metal. These minerals are described using ters that refer to commonly known qualities. Waxy: The mineral looks like paraffin or wax Vitreous: The mineral looks like broken glass. Pearly: The mineral appears iridescent, like a pearl. Silky: The mineral looks fibrous, like silk. Greasy: The mineral looks like oil on water. Resinous: The mineral looks like hardened tree sap (resin). Adamantine: The mineral looks brilliant, like a diamond Odor: most minerals have no odor. Taste: only soluble minerals have taste. Specific Gravity: the comparison or ratio of the weight of the mineral to the weight of an equal amount of water. For the upcoming weeks we will be looking at the twelve beautiful stones we offer in our mind, body and spirit collections. We will look at their classification and identification, their chemical composition, their crystal system and their unique healing attributes. Pick up the minerals around you. Take in their energy. Touch them, feel them in the palms of your hands. Think about the miracle in which they where created. Be grateful for this gift from the earth. *A special thanks and recognition to all of the great writers in this field. My information is a compilation of bits and pieces from the many books and online information out there. I am so grateful for all of the insight.*