Semi-Centennial Volume. 87 



Agate, we recognize three varieties — Onyx, that variety which is 

 always variegated, that is, having distinct bands or lines. Onyx 

 is always banded with white and either black or brown lines. 

 If it was colored otherwise, it would hot be called Onyx. Sar- 

 donyx, just like onyx, only that the bands are of white and red 

 or white and pink or these three colors together. Do not con- 

 fuse Jasper with the banded agates, although it is just like the 

 agates in everything except that the Jasper has bands of blue or 

 green and the wise men who have named the gems have not 

 seen fit to call Jasper an agate. Then we have also Moss Agate. 

 This is a clear stone; it may be almost either of the above 

 classes, but is flecked with spots of moss or other particles 

 which give it distinct colorings. 



These fifteen subclasses then are all quartz, and he who would mas- 

 ter a common knowledge of stones should bear in mind that no matter 

 which of them he should have at hand, it is essentially quartz and only 

 quartz. He should bear in mind that these are all of various shapes 

 and forms, colors and variegations, but they have all the common char- 

 acteristics and composition of the great mother class, Quartz, which is 

 recognized reasonably easy. 



Calcite is the second most abundant rock-forming material. It is 

 found all over the world and is one of the most common elements of the 

 rocks of our state. It is the major material of our limestones and 

 chalks, the substance of shells and the marbles. It is a gray or nearly 

 white floury material, which is sometimes very soft and can easily be 

 cut with a knife. It occurs sometimes in crystalline form ranging in 

 various colors through blue, green, black or yellow. Calcite is sometimes 

 incorrectly called spar, but there is quite a diff'erence, as we shall pres- 

 ently see, when we examine that substance. In chemical composition it 

 is a carbonate of lime. Under the action of any acid it has the prop- 

 erty of eff'ervescing, liberating carbonic acid gas. Its crystals, while 

 very beautiful, are of no use in the arts, as they are too soft and will 

 not retain a polish. 



Feldspar is, perhaps, the third most common and important rock- 

 forming material. It occurs most commonly as a cement in the mak- 

 ing of other rocks. It has a pearly luster, not glassy like quartz. It is 

 also less hard, but much harder than calcite. It can be scratched with 

 a sharp knife. It weathers more easily than quartz and in weathering 

 it crumbles in grains, is a granulated substance and not a floury or dusty 

 substance like calcite. It is the pearly substance of the granites and 

 gneisses, and with quartz is the cement that cements the materials 

 of the large red boulders found in the northern counties of Kansas, mis- 

 called "niger heads." It occurs in various colors and gives its color to the 

 rock it constitutes. In chemical composition it is a silicate of alumina. 

 Some of its valuable crystals, though not found in Kansas, are the moon- 

 stone, a beautiful opalescent gem when properly polished, and the 

 Amazon stone, a beautiful blue-green crystal found near Pikes Peak, 

 Colorado. 



Mica is an important rock-forming material and is probably recog- 

 nized at sight by most of us on account of its utility in glazing stove 

 doors, automobile curtains, etc. It has a perfect cleavage and will scale 



