Gemology - Colored Stones - Assignment3-6 Exam Questions with Correct Answers

A unit cell defines a mineral's A. size. B. habit. C. shape. D. basic identity. Correct Answer D. basic identity. If a crystal grows in a flux that is highly saturated with the necessary elements, it tends to be A. large. B. small. C. terminated. D. well formed. Correct Answer B. small. Which aggregate's crystals are visible only with magnification greater than a standard gemological microscope's? A. Mesocrystalline B. Megacrystalline C. Microcrystalline D. Cryptocrystalline Correct Answer D. Cryptocrystalline Which is classified in the orthorhombic crystal system? A. Beryl B. Topaz C. Garnet D. Corundum Correct Answer B. Topaz Which element causes red in ruby and green in emerald? A. Calcium B. Potassium C. Chromium D. Magnesium Correct Answer C. Chromium Which type of twinning is caused by environmental change after the gem forms? A. Cyclic B. Primary C. Penetration D. Polysynthetic Correct Answer D. Polysynthetic Which type of twinning looks as if two crystal halves are mirror images? A. Cyclic B. Contact C. Penetration D. Polysynthetic Correct Answer B. Contact Needles of actinolite found in emerald are classified as A. cleavages. B. inclusions. C. penetration twins. D. impurity elements. Correct Answer B. inclusions. A two-phase inclusion is a cavity in a gem that's typically filled with a A. pair of liquids. B. gas and a solid. C. liquid and a gas. D. liquid and a solid. Correct Answer C. liquid and a gas Atoms in a gem that are not part of its essential chemical composition are A. unit cells. B. inclusions. C. trace elements. D. chemical compounds. Correct Answer C. trace elements. The trace elements that cause corundum's blue are A. iron and titanium. B. chromium and iron. C. aluminum and oxygen. D. aluminum and chromium. Correct Answer A. iron and titanium. An object's weight in relation to its size is called its A. density. B. carat total. C. atomic index. D. specific gravity. Correct Answer A. density. Which gems are cryptocrystalline aggregates? A. Opal and amethyst B. Nephrite and jadeite C. Sugilite and lapis lazuli D. Chalcedony and turquoise Correct Answer D. Chalcedony and turquoise