86 Kansas Academy of Science. 



names were, their composition, their common characteristics and how 

 they were placed there. I made up my mind that if I was ever able to 

 name and distinguish them, I would do my best to make it easier for 

 others who might be troubled like I was. Hence the reason for this 

 paper. 



It may sound strange to some of us, but Kansas has nearly all the im- 

 portant rocks in some form or condition. Outside of a very few rare 

 gems or crystals, I have found in Marshall county the major classes of 

 all rocks and also most of their subclasses. 



I want to make clear in the beginning the classification of five com- 

 mon kinds ot rock. Of course there are many, many more than this, but 

 this will suffice us now for this first lesson. We should learn to dis- 

 tinguish and classify the following: Quartz, calcite, feldspar, mica and 

 hornblende. If we learn these five great classes thoroughly, we will be 

 in a fine way to become competent petrologists and able to identify most 

 of the common rocks found in our state. I will take these up singly and 

 discuss their common characteristics, their composition and their various 

 subclasses. 



Quartz is one of the most common and abundant. It is quite easily 

 recognized by its very hard, glassy, lustrous appearance. Pure, clear 

 quartz is easily recognized, but the young petrologist is at times con- 

 fused by its many subdivisions, with its many colors, variegations and 

 forms in, which it is found. Quartz is very hard, will scratch glass and 

 cannot be cut or indented with a knife blade. It has no regular cleav- 

 age, always breaking irregularly. It is the essential constituent of many 

 other rocks, as granite, gneiss and the sandstones. It is in many in- 

 stances the cement which binds together the other elements into one 

 mass or stone. In chemical composition it is a union of oxygen and 

 silicon, nearly the same elements of our Portland cement. We recognize 

 fifteen different varieties or subclasses: 



Black Quartz, a smoky or black variety. 



Yellotv Quartz, a clear variety, but yellow or citron colored. 



White Quartz, or Milk Quartz, a white, milky colored variety. 



Rhinestone, a clear, brilliant variety, also called Water diamond, 

 Cape May diamond, or Lake George diamond. 



'Amethyst, a beautiful clear purple variety. 



Cornelian, a red, waxy variety. 



Opal, a white variety, opalescent, with a beautiful play of colors. 



Chalcedony, almost like carnelian, but a duller color, not so clear. 



Chrysoparse, a chalcedony, but of apple green color. 



Heliotrope, a dark green variety, not transparent, flecked with red 

 spots and commonly called bloodstone. 



Jasper, an opaque variety, often banded, and in blue or green 

 colors. 



Flint, a dull, impure variety of dark gray or black color. 



Chert, also a dull flint or purer variety, but very brittle. 



Cat's Eye, the substance of silicified trees, which when highly 

 polished, gives a play of colors like a cat's eye, hence the name. 



