Latest News
- Improved Outlook to be Seen at PDAC 2010
- Picking Out Flawed Gems
- Great Expectations for Great Panther Silver
- Bye-Bye Dubai
- Bin’ Travellin’
- New Developments and Talking Heads in the Resurgent Commodity Boom
- 2009 Toronto Resource Investment Conference
- A REEally Interesting Commodity Market
- Whose Land is it Anyways?
- The Summer Exploration Season – Sans Fanfare
5034 Aappaluttoq Aber Diamonds ABX ACS AEM Ag Agnico-Eagle Mines Agrium Alto Ventures Amarillo Amaruk AMEC Amerigo Archangel Diamond Archon Minerals Ltd. Arctic ARG Argentina Argyle Ashton Mining Canada ATV ATW ATW Venture Corp. Au Australia AUY Avalon Rare Metals Avanti Mining Corp. Aviat AVL Barrick Bathurst Beluga BHP BHP Billiton Bling Blue Note Mining Blue Pearl Cluster BN BRIC Buenaventura BVN Canada Candente carbonatite Caribou Castillian CCE Chariot Resources CHD Chidliak Chile Chris Jennings Chuck Fipke Churchill Churchill craton CL Co Codelco Coloured Gemstones Commerce Resources Contact Diamond Corporation copper Cu DDN DeBeers Diamond Diamondex Diamonds Diamonds North Dianor Diavik Diopside dividend DNT DO-27 DOR DSP Eastmain Resources Ekati El Teniente emerald ER EuroZinc Exotic Metals FALC FGT First Nickel Inc. Fiskenaesset FNI FNV Forest Gate Fort a la Corne Foxtrot Franco-Nevada G Gahcho Gahcho Kue Gem Diamonds geologic terms glossary gold Goldcorp GPR Great Panther Resources Great Panther Silver Greenland Grib Gualcamayo Guanajuato Guaniamo Harry Winston Hawthorne Gold Hearne HGC Hibou HUD Hudson Resources Hunter Exploration HW HWD IME In Indicator Minerals indium interview iron Jericho Jericho Diamond Mine Jigsaw K K-2 Kahuna Kennady Lake Killiq kimberlite Kinross Lac De Gras Las Aguilas lead Leadbetter Letseng Li limestone lithium Lockerby LUC Lucara Lukoil LUN Lundin Mining Lynx Mapimi Marifil Mines Ltd. market hype MAT Matamec Exploration Inc. Metalex Ventures Mexico Mexivada MFM Mina El Carmen Mo molybdenum Monument Diamond Project Motapa Mothae Mountain Province Diamonds MPV MTP MTX Muskox Kimberlite natural gas Nb NEM Neuqen Basin New Gold Newmont New Nadina Diamonds Ltd. NGD Ni NI 43-101 nickel niobium NMC NNA Notch Nunaminerals Nunavut oil Orion Otish Pascua Llama Pb PC Gold Pd PDAC Pedernal Peregrine Diamonds PGD PGE PGM PKL placer platinum Pogo Mine potash Potash Corp. pre-feasibility PST003 Pt Punta Colorado Qavvik Qilaq QUA Quadra Mining QUC Quebec Quest Uranium rare earth elements Rare Element Resources Raytech Metals Corp. Re REE Renard RES Restigouche rhenium Rio Colorado Rio Narcea Rio Tinto RSC RTP ruby San Antonio San Juan San Roque sapphire Saskatchewan SGF Shear Minerals Shore Gold silver SL Snap Lake Sola Resource Corp SOQUEM Inc. SRM Star Stewart Blusson stockhouse.com Stornoway Diamonds Strange Lake Strateco Resources SWY Ta TAH Tahera tantalum TCK.A TCK.B TCM Teck Cominco Terrane Metals Tesla TGX Thompson Creek Metals Thor Lake TIF Tiffany & Co. Topia Topia Mine True North Gems TRX Tsa Da Glisza Tuktu Tuktu-1 Tunerq tungsten Tuzo U uranium VALE-INCO Veladero Venezuela Victor WDO Wesdome Western Troy Capital Resources WRY WWW International Diamond Consultants Ltd. Yamana Gold Inc. YRI zinc Zn
Categories
Monthly Archives
Sponsors
Glossary of Geologic Terms
Posted by David
Previous - 1 - 2 - 3 - 4 - Next
1. aeromagnetic
Aeromagnetic surveys are a geophysical remote sensing technique that employ helicopter or airplane magnetometers to measure the variance in the Earth's magnetic field caused by near surface geology. Different rocks have different minerals that can have different magnetic properties. Kimberlitic rocks typically have a significantly different magnetic signature than common rock types found at the Earth's surface. These show up as magnetic anomalies on the survey map.
2. c/t
Carats per metric ton. One of the two main ways that diamond grade is expressed. The other is cpht: carats per one hundred tons.
3. carat
The unit of weight by which diamonds are classified. One carat equals 0.2 grams. This terminology is derived from the carob seed. This was a seed of fairly constant mass and they were used as a counterweight when weighing gemstones in pre-modern times.
4. carbonatite
This is an igneous rock characterized by an abundance of carbonate (CO3) minerals (e.g. calcite, dolomite, siderite, etc.). This is in contrast to the vast majority of igneous rocks that are dominated by silicate (SiO4) minerals (quartz, feldspar, olivine, pyroxene, mica, etc.). Carbonatites are relatively rare, but can contain minerals that are important sources of rare earth elements (REEs), niobium, tantalum, gold, and uranium. These rocks can also share some petrologic similarities with kimberlites and pegmatites.
5. craton
These are the cores of the continents. They are old (at least 500 million years old) and stable sections of crust. They often have very deep "keels" in their centres where the lithosphere becomes very thick. They are mostly composed of crystalline crustal rock such as granite. When two cratons collide and a mountain chain is built, this is an orogen. Examples of important cratons are the Superior and the Churchill that make up most of the Canadian Shield. The Slave craton in the Canadian Arctic is of particular importance as it contains the most significant diamond deposits to date. Diamonds in Russia are found mostly in the Siberian craton. Diamonds in southern African are found mostly in the Kaapvaal and Zimbabwe cratons.
6. diamond
The mineral form of native carbon at high (mantle) pressures and temperatures. It crystallizes in the isometric crystal system. There are two primary growth habits of diamond: octahedra and cubes. Octahedra are dominant. Diamond has a strong octahedral {111} cleavage. Diamond is a pseudormorph of graphite and is the hardest naturally occurring substance known. Although primarily made of carbon, impurities are common and may affect the appearance of the stone. Nitrogen, the most common impurity, can impart a yellow colour, boron in less amounts can cause a blue colour (e.g. the Hope diamond). Hydrogen imparts a purple to gray tinge. Other factors can also cause coloured diamonds. Numerous graphite inclusions cause black diamonds. Deformation of the crystal structure due to stresses in the mantle result in brown, pink, or red diamonds. Breakdown of the crystal (termed becoming metamict) due to radiation damage causes greenish colouration. Coloured diamonds are called fancies.
7. diatreme
This has two meanings. In a structural sense it refers to the inverted conical or "carrot" shaped body typical of many kimberlite pipes. Although the shape can very strongly from the South African model. Fort a la Corne kimberlites are very wide and have a "coupe-style" champagne glass shaped cross-section. Gahcho Kue kimberlites are very irregular. The second meaning is petrological. This refers to the facies of kimberlite in-filling the diatreme. It is often refered to as a tuffisitic breccia. This can be intrepreted as a volcanic rock full of angular xenoliths, mantle and crustal. In the general model of a kimberlite body. diatreme facies kimberlite lies below the crater (pyroclastic) facies kimberlite and above the root zone of hypabyssal kimberlite.
8. eclogite
High grade metamorphic rock. Primarily composed of omphacite and pyrope-almandine-grossular garnet. Kyanite, coesite, corundum, and orthopyroxene are rare accessory minerals.
9. G10
see garnet
10. G5
see garnet
Previous - 1 - 2 - 3 - 4 - Next