58 
ALASKAN MINERAL RESOURCES IN 1905. 
Several distinct though related granite types are found, in all of which plagioclase feldspar 
is an essential constituent. Hornblende is the usual dark mineral, though biotite mica is 
often present and in rare instances exceeds in amount the hornblende. Quartz is com- 
monly present, though usually in small amounts. The accesssory components are apatite, 
titanite, and magnetite; secondary minerals, due to general metamorphism, are sericite, 
epidote, zoisite, chlorite, and calcite. Petrographically the rock is often related more • 
closely to the diorites than to the true granites and is often referred to as a diorite. 
The prevailing color of the granite is a light gray and only in rare instances were pink or j 
reddish masses observed. The grains of the component minerals are ordinarily of medium 
size, not differing greatly in the different localities. Evidence of the durability of the 
granite is afforded in many places where long exposure to the influences of weathering . 
has caused little or no disintegration of the surface. 
Investigations of granite or other building stones have been meager in southeastern 
Alaska, principally because of a lack of knowledge of their value. In the large cities bor- I 
dering the Pacific coast the increasing use of stone for building purposes has created a 
widespread and growing demand. The controlling factor in the successful operation of ] 
a quarry is often not the intrinsic value of the stone, but rather its market price and the 
position of the quarry relative to the market. The actual cost of stone depends on the 
case of quarrying in blocks of the required form and the facility with which the stone can 
be dressed. Other factors, such as the color, durability, and susceptibility for taking a 
high polish, also govern its value. It is seldom that all the stone of a quarry is of uniform 
grade, and sorting it into classes is usually necessary. The large flawless blocks are of 
most value for monumental purposes. For building and construction works blocks of j 
smaller size are used and the market value is considerably less. The smallest material 
and inferior grade of rock are often of value as paving stone or for road metal. 
The following table shows the average value of granite and the production of 1904 in 
the three most western States, with which Alaska will probably enter into competition: 
Average value and production of granite in 1904 in California, Oregon, and Washington. a 
Total production. 
Average value ai quarry per 
cubic foot 
Sold rough, foi 
Sold dressed, for— 
Building. 
Monumen- 
tal. 
Other 
purposes. 
Building. 
Monumen- 
tal. 
Curbing. 
$72,115.00 
.85 
$63,014.00 
.98 
$222,351.00 
$421,394.00 
3.25 
$137,658.00 
4.80 
$80,653.00 
*>.85 
^Compiled from Mineral Resources U. S. for 1904, U. S. Geol. Survey, 1905. p. 814. 
b Per linear foot. 
The above values do not represent the market value of the stone laid down in the cities 
along the coast, as the cost of transportation from the quarries is not included. From 
most points in southeastern Alaska where granite occurs the facilities of loading the quar- 
ried stone directly into ocean-going vessels are exceptionally favorable and a freight rate 
of from $1 to $2 per ton can be obtained. Investigation of this as yet undeveloped 
resource of the region is to be recommended. 
GYPSUM. 
The increasing use of gypsum as a building material, together with its importance as 
a wall plaster and fertilizer, makes it of increasing commercial importance. 
