Geol. 115 Study Guide for Lesson Three

What do you need to know (meaning understand, not just memorize) to do spectacularly well on Quiz 3? The essential terms and concepts are listed below. Writing out answers to each of the following would be an excellent way to prepare.

(Be able to define or recognize the definition of these terms and understand their useage in context). You can find the information in the web lesson -- on your test, do not expect exactly the same wording or examples as in your lesson. It would be a good idea to cross reference the defintions in the lesson with those you find in the texts.)

1) Essential Vocabulary

amorphous, crystalline, metamict, glass, tektite, aggregate, crystal system, crystal lattice, axis, unit cell, habit, acicular, prismatic, dendritic, drusy, botryoidal, massive, polymorph, twin, negative crystal, phantom, pseudomorph, silicate, oxide, phosphate, carbonate, native element, cleavage, fracture, conchoidal, hardness, Mohs' Scale, toughness, stability, crazing, stress fracture, quench crackle, specific gravity, hydrostatic weighing, heavy liquids, hot point test, thermal conductivity

2) Essential Concepts

From what do the physical properites of gems derive?, amorphous gems vs single gems crystal and examples, aggregates: micro and cryptocrystalline and examples, mineral vs rock, recognize the names of the seven crystal systems, in general, how do they differ from each other?, relationship between unit cell, crystal system and crystal habit, be able to recognize the following habits: cube, octahedron, acicular, prismatic, dendritic, drusy, botryoidal, massive, summarize the factors which control crystal growth, distinguish between polymorphs, twins, phantoms, negative crystals and pseudomorphs, recognize appearance of and examples of each, be able to assign a gem to one of five chemical groups based on looking at its chemical formula (silicate, oxide, phosphate, carbonate, native element), cleavage vs fracture, types of each, what are the three factors of gem durability, how is each described with relevant examples, how is knowledge of these factors of durability useful (examples), what is specific gravity, why do gems differ in this regard, how is it measured? pros and cons of each SG method, for which gems would testing thermal reaction, thermal conductivity and electrical conductivity be useful, why?

3) Pronunciation Guide

(Clicking on the term will temporarily take you to a new web page to hear the pronunciation of the word. Depending on your browser configuration either put away the audio window, or use the back button to return to the list.)

Moldavite, chalcedony, drusy, uvarovite, cryptocrystalline, acicular, rutile, mesolite, botryoidal, maacle, lepidocrosite, Goethite, chrysoberyl, apatite, conchoidal, Charoite, Mohs, kyanite, sphalerite, chrysoprase, nephrite, meerschaum, Andalusite, scheelite, angelsite, cassiterite, chrome diopside, Moissanite