ii4 



THE GUIDE TO NATURE. 



Calcite : — Monticello Mountain, on 

 which stands the historic home of 

 Thomas Jefferson, is about two miles 

 southeast of Charlottesville. The 



VIEW IN MONTICELLO QUARRY 



Showing veins of quartz and calcite in 



chloritic schist. 



mountain is one of a range formed of 

 an ancient igneous rock now highly 

 metamorphosed. The most conspic- 

 uous minerals composing the rock are 

 quartz, chlorite, and epidote, so that 

 its color varies from the grass green of 

 the chlorite to the "bull-frog green" 

 of the epidote. Near the foot of the 

 mountain where the road crosses 

 Moore's Creek the rock is exposed by 

 the road cut. Here small veins of 

 calcite traverse the rock. On opening 

 up along these veins, crystallized cal- 

 cite in fair examples was found. The 

 specimen in my cabinet is a small 

 pocket in the schist lined with cal- 

 cite crystals. The little cavern of white 

 crystals against the green background 



makes a unique and attractive speci- 

 men. 



Chlorite: — As we follow the same 

 road at the point where it starts up 

 the mountain and the creek makes a 

 bend and skirts around the base of the 

 mountain, the Charlottesville rock 

 quarry is situated. A good deal of 

 rock has been taken out for road metal 

 and the consequent exposure is 70 or 

 80 feet high and about 50 yards long. 

 Along the wall were found cross 

 sections of irregular veins of chlorite. 

 The mineral is very soft, dark green — 

 almost black on a fracture surface — 

 though the streak is grass green. It 

 seems to be composed of very small 

 scales tightly packed together. It is 

 apparently very pure; but it has not as 

 yet been identified as a particular 

 chlorite. It is hoped that a chemical 

 analysis as soon as practicable will 

 determine this point. 



Specular Hematite: — Quartz veins 

 are common in the chloritic schist and 

 crystallized hematite has been fre- 

 quently deposited in fissures in the 

 quartz. On the road side near the 

 Monticello gate two pieces of milky 

 quartz were found and on them con- 

 siderable specular hematite. Equally 

 rich masses have not been found in 

 place. 



Quartz : — Quartz does not occur in 

 large distinct crystals; but some inter- 

 esting massive varieties are mentioned 

 below. Beyond the Monticello en- 

 trance, however, a narrow dike of 

 quartz porphyry cuts through the 

 chloritic schist. On the joint planes of 

 the porphyry small crystals were found 

 implanted, most of which approach 

 the normal form. Smoky quartz was 

 found along the Monticello road side. 

 The mass is almost black and on parts 

 of the fracture surface the lustre is 

 almost dull. It seems probable that 

 the smokiness is due to included black 

 hornblende or possibly tourmaline. 

 Following this same road past Mon- 

 ticello, the old Virginia home named 

 "Morven" is reached. Many pieces of 

 amethyst, large and small, have been 

 found on this place. I am indebted to 

 a lady of the neighborhood for a speci- 

 men, weighing 8^2 ounces. In struc- 

 ture it is a mass of crowded and fre- 



