Quartz has a characteristic conchoidal fracture, yet rock shops often sell quartz as elongate six sided objects with a pointed termination. what causes this shape? a. quartz usually is amorphous, consistent with its conchoidal fracture, but when it grows it grows against minerals with planar faces, causing this shape. b. the rock shop cuts them that way with abrasives. the facets are cut to give the crystals more "power" for the crystal people. c. the planar faces that form the object are crystal faces that grow when the crystals grew into a void. d. you should never buy a crystal like this because it is clearly fake, only artificial crystals grow this way.

C. The planar faces that form the object are crystal faces that grow when the crystals grew into a void.

Explanation:

Quartz is considered the most abundant mineral on earth. Its best known form is quartz crystals, similar to broken glass pieces. Quartz formations are part of a geological process that can take thousands of years. Quartz stones are mainly composed of Silicon Dioxide (SiO2), being present in all types of rock formations on the planet, whether igneous, metamorphic or sedimentary. Quartz is sold as six-sided elongated objects with a sharp end, this shape is caused because the flat faces that form the object are crystal faces that grow when crystals grow in a void.

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explanation:

hey bro i looked it up on google the structure of the eye-spot in euglena viridie, e. ehrenbergii, and phacus pyriyorme is not as franzé haa described it. the so-called “crystal body” and “lens bodies” were not found in any of the individuals of the species examined by me. as earlier observers have stated, the eye-spot consists simply of a mass of pigment granules arranged in a single layer, and probably embedded in a protoplasmic framework, but the latter could not be seen, and its presence was only inferred from the fact that the pigment granules must be held together in some way, thd the eye-spot as a whole is capable of expansion, and that the pigment granules can be separated from each other.

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