BETA

Blue Mountain Granite

Submitted by Ed FitzGerald on Tue, 2015-01-13 14:39
Stone Type (Commercial): 
Availability: 
Available
Physical Data
Absorption (%): 
0.26
Modulus of Rupture, Dry (psi): 
2,648
Compressive Strength, Dry (psi): 
7,238
Bulk Specific Gravity: 
2.75
Geology
Grain Shape: 
Angular
Grain Size: 
Coarse
Medium
Petrographic Description: 

Specimen: 2014-081-1
This is a metamorphic rock. No foliation is visible in this thin section, but this may be due to orientation of the sampled section. The rock is composed principally of quartz, feldspar, biotite, garnet, opaques, amphiboles, and pyroxenes. Quartz and feldspar account for about 70 percent of slide area. Grains are mostly xenoblastic with curving boundaries and random orientation. Maximum grain size is 2 mm (feldspar porphyroblast), modal size covers a significant range from about .15 to .75 mm. Many of the quartz grains present strain induced wave extinction. Many of the smaller grains may reflect strain induced nucleation. The relative amount of feldspars and quartz is difficult to estimate due to similar appearance. Observed feldspar twinning was rare but both plagioclase and potassium feldspar varieties are present. The accessory mineral composition is fairly diverse. Garnet is the most common and has a maximum crystal size of 2.4 mm. Biotite is the also common and occurs in aggregates up to 1.2 mm in maximum dimension. A variety of amphiboles are present as indicated by cleavage planes including fairly common hornblende. Pyroxenes, also identified by cleavage, and includes both monoclinic and orthorhombic forms (extinction and birefringence value). Epidote is present in very low quantities. Alteration products are visible along cleavage planes in biotite and the amphiboles and pyroxenes. Feldspars present some minimal sericitization along cleavages and pressure cracks.
MP 9/4/2015

Specimen: 2014-081-2
This is a metamorphic rock. No foliation is visible in this thin section, but this may be due to orientation of the sampled section. The rock is composed principally of quartz, feldspar, garnet, biotite, opaques, amphiboles, and pyroxenes. Quartz and feldspar account for about 60 percent of slide area. Grains are mostly xenoblastic with curving boundaries and random orientation. Maximum grain size is 4.4 mm (quartz), modal size covers a significant range from about 1.5 to .4 mm. Many of the quartz grains present strain induced wave extinction. Many of the smaller grains may reflect strain induced nucleation. The relative amount of feldspars and quartz is difficult to estimate due to similar appearance. Observed feldspar twinning was predominantly tartan. The accessory mineral composition is fairly diverse. Garnet is the most common and has a maximum crystal size of 2.8 mm. Various species of amphibole, including hornblende are the next most common accessory mineral. Clinopyroxenes and orthopryoxenes as well as biotite and opaques are less common but present. What is likely epidote is present in very small amounts. Feldspars present some sericitization along cleavages and pressure cracks.
MP 9/4/2015

Specimen: 2014-081-3
This is a metamorphic rock. No foliation is visible in this thin section, but this may be due to orientation of the sampled section. The rock is composed principally of quartz, feldspar, garnet, amphiboles, opaques, biotite, and pyroxenes. Quartz and feldspar account for about 70 percent of slide area. Grains are mostly xenoblastic with curving boundaries and random orientation. Maximum grain size is 6.2 mm (feldspar porhphyroblast), modal size covers a significant range from about .7 to .15 mm. Many of the larger quartz grains present strain induced wave extinction. Many of the smaller grains may reflect strain induced nucleation. This is especially visible on the margins of several large quartz porhpyroblasts that now have sutured boundaries. In other localized areas a texture nearing granoblastic polygonal is predominate, suggesting complete recrystallization. The relative amount of feldspars and quartz is difficult to estimate due to similar appearance. Observed feldspar twinning included both tartan and polysynthetic. The accessory mineral composition is fairly diverse. Garnet is the most common and has a maximum crystal size of 4.4 mm. Various species of amphibole, including hornblende are the next most common accessory mineral. Clinopyroxenes and orthopryoxenes as well as biotite and opaques are less common but present. What is likely epidote is present in very small amounts. Feldspars present some sericitization along cleavages and pressure cracks. One very large grain of feldspar presented chlorite and other alteration products.
MP 9/4/2015

Specimen: 2014-081-4
This is a metamorphic rock. No foliation is visible in this thin section, but this may be due to orientation of the sampled section. The rock is composed principally of quartz, feldspar, garnet, amphiboles, opaques, pyroxenes, and biotite. Quartz and feldspar account for about 70 percent of slide area. Grains are mostly xenoblastic with curving boundaries and random orientation. Maximum grain size is 2.6 mm (quartz), modal size covers a range from about .5 to .2 mm. Many of the larger quartz grains present strain induced wave extinction. Many of the smaller grains may reflect strain induced nucleation. This is especially visible on the margins of several large quartz porhpyroblasts that now have sutured boundaries. The relative amount of feldspars and quartz is difficult to estimate due to similar appearance. Observed feldspar twinning was predominantly tartan. The accessory mineral composition is fairly diverse. Garnet is the most common and has a maximum crystal size of 1.2 mm. Various species of amphibole, including hornblende, are the next most common accessory mineral. Clinopyroxene and orthopryoxenes (hypersthene?) as well as opaques are less common but present. Epidote and biotite are present in very small amounts. Feldspars present some sericitization along cleavages and pressure cracks. Mafic minerals are moderately altered to iron hydroxides and oxides.
MP 9/4/2015

Images

Thin Sections

Quarry

NOTE: Quarry locations are approximate.

Adirondack Natural Stone Quarries
8986 State Rt. 4
12887 Whitehall , New York
United States
43° 28' 52.8888" N, 73° 25' 48.108" W
New York US

Report an Issue

CAPTCHA
Type the words or phrase shown below to verify that you are not a robot.