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February 20, 2013 AGATES To be or not to be, that is the question By Jenn Jedidiah Free One of my absolute favorite stones is agate. They come in just about all patterns and colors. A close second is jasper. Those, too, are found in all patterns and colors. But what exactly is an agate? And what is the difference between an agate and a jasper? Both agates and jaspers are varieties of quartz known as chalcedony (pronounced Cal-Sidney). Silica Dioxide (SiO2), also known as quartz, is one of the most common minerals in the earth���s crust. There are two major types of quartz: macrocrystalline, meaning ���large crystal���, and cryptocrystalline, meaning the crystals are too small to be seen with the naked eye. Examples of macrocrystalline quartz are clear quartz, smoky quartz, citrine, amethyst and others. Chalcedony and its varieties are crypto- or micro- crystalline forms of quartz. Technically, the term Chalcedony includes any type of cryptocrystalline quartz, however in the gemstone world it is only used to describe whitish or light blue translucent material. Chalcedony has a hardness of 7 on the Mohs scale. Both agates and jaspers are varieties of chalcedony in the technical sense- they are cryptocrystalline forms of quartz. This brings us to our original question: If they are both chalcedony, then what is the difference between them? This is a good question, because in some cases the difference is well de���ned, but in others it is not. Technically, the primary difference between an agate and a jasper is diaphaneity ��� a word used to describe ���how easily light passes through a material���. There are three speci���c levels of diaphaneity: transparent, translucent, and opaque. Microcrystalline quartz in its pure form www.DesertMessenger.com ADVENTURES WITH ROCKS is semitransparent. When impurities or foreign materials are added from the surrounding rocks and minerals, the color of the microcrystalline quartz changes and the ability of light to pass through it decreases. Agate is a translucent to semitransparent chalcedony, which means light will pass through it. Agates typically have variegated, wavy, or irregular bands, but sometimes the bands are not visible, or instead of bands, the stone has dendritic, plume, or mossy inclusions. Agates form in areas of volcanic activity where water rich in dissolved silica (SiO2) ���ows through cavities and fractures in igneous rock such as basalt and rhyolite. The silica-rich solution leaves layers of silica gel on the walls of these cavities, which slowly crystallize and build up. As the mineral composition of the silica (other minerals, or impurities, carried with the SiO2 in the water) changes over time, the color of the microcrystalline quartz is altered, forming different colored layers (bands) or inclusions. Jasper, on the other hand, is an opaque variety of chalcedony. Jasper contains enough impurities (other minerals besides silica) to make it opaque. So the real difference between jasper and agate is the amount of impurities that are in the specimen. Also, rather than in cavities in igneous rock, jasper typically forms in soft sediments when ���ne particulate materials are deposited and cemented into a solid mass by the silica. The colors and patterns of jasper are determined by the mineral particulates in that mass. But agates and jaspers will not always conform themselves to our classi���cations. In many instances, jaspers have translucent zones, or areas where agate has developed. Some agates can be mostly opaque with a few bands ��� SEE AGATES PAGE 29 3rd quarter at Salome High February is a month to show compassion, love, and hard work. Most of the students recognize the important dates of the month, such as World Cancer Day, World Day of the Sick, World Day of Social Justice, Valentine���s Day, and World Peace and Understanding Day. There are many interesting facts about each date that could entertain you on a long day. There are not a lot of fascinating events going on at Salome High School. We have started our Softball, Baseball, and Track seasons, AIMs testing is soon, and selected students in different culinary classes are attending a Cooking Competition. The girl���s Basketball team has quali���ed for the state tournament, and will be playing February 16th. Their Current record is 23-5. They have done a great job. Way to go Frogs! The season for Softball, Baseball, and Track is here! A large number of students were excited to have practice begin, but due to weather changes some practices are short, or cancelled. The Softball and Baseball teams have their ���rst game in February 23rd. Every student has put in their best effort to keep their grades up, and to try their hardest on and off the ���eld. A lot of students are pushing themselves to succeed. We all look forward to a great season. Go Frogs! There are ���ve students from two different culinary classes that were chosen to attend the Cooking competition at Arizona Western College in Yuma, AZ. There will only be four students that will actually be cooking, but the last student will be allowed to watch the progress of their classmates. The four students will be split into different groups so that they will not be working in the same kitchen. The four students will be awarded time to demonstrate knife cuts, and the rest of the time they will spend preparing a salad, Page 27 and chicken Piccota. The students all have the chance to show others their kitchen skills, and to have a blast with something they may love to do. AIMs testing will be February 25th and February 26th. The Reading test is held that Monday, while Tuesday is the Writing test. Every student has done their best to prepare themselves for these tests. We all have the hope of being average or higher to show our loved ones how much we learn here at Salome High School. Many students do not want to repeat AIMs next year, which is rumored to be harder. Building Trades has been working on a house in Indian Hills area. They will be having an open house on February 28th to show their completion of the house. The house will be sold using the sealed bid process. For more information contact the school at 928-859-3453. All of the seniors are preparing for their graduation. They have been attending College Fairs, FAFSA���s, and have been ���lling out quite a few College applications. Most students are thrilled to be preparing for their lives, and have been talking about their plans. They all seem to have everything set out and have their goals in order. The seniors have taught the lower classmen a lot about respect, and a lot of the lower classmen look up to the seniors for advice on surviving high school. Thank you seniors for teaching the younger classmen valuable life lessons that we can carry out with us for the rest of our lives. UPCOMING EVENTS ��� College Fair for Juniors and Seniors at Bagdad February 20th ��� Culinary Competition Feb. 22nd ��� Baseball and Softball Game against River Valley 4-6 p.m. Feb. 23rd ��� AIMs Reading and Writing testing Feb. 25th - 26th ��� Sports Banquet Feb. 26th at 6 p.m. ��� Track Meet February 27th ��� ASU & Glendale Field trip Feb. 28th ��� End of Third Quarter March 8th ��� Spring Break March 11th ��� 15th READER���S OASIS BOOKS 928-927-6551 690 E. Main - Quartzsite (one block east of Family Dollar)