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Adirondack Granite

Submitted by Ed FitzGerald on Tue, 2015-01-13 13:44
Stone Type (Commercial): 
Availability: 
Available
Physical Data
Absorption (%): 
0.28
Modulus of Rupture, Dry (psi): 
1,432
Compressive Strength, Dry (psi): 
9,750
Bulk Specific Gravity: 
2.80
Geology
Grain Shape: 
Angular
Subangular
Grain Size: 
Coarse
Medium
Petrographic Description: 

Specimen: 2014-080-1
This is a metamorphic rock. No foliation is visible in this thin section, but this may be partly due to orientation of the sampled section. The rock is composed principally of quartz, plagioclase-feldspar, biotite, and garnet. Quartz and feldspar account for about 85 to 75 percent of slide area. Grains are mostly xenoblastic with curving boundaries and random orientation. Maximum quartz grain size is 2.2 mm, modal size is from about .4 to 1.3 mm. Many of the larger 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. The only observed feldspar twinning pattern was polysynthetic, suggesting relatively few to no potassium feldspars. Biotite occupies about 10 percent of slide area. Modal biotite size is around .3 mm. There is a pronounced orientation preference with cleavage planes parallel to the thin section. The high reddish hue of the biotite may suggest a relative high titanium content. Garnets are xenoblastic to hypidioblastic, up to 2.8 mm in size, and are intergrown with more common phases. The only other mineral present are extremely rare opaques. Feldspars show only the faintest signs of incipient weathering, with a dusty appearance and very minimal sericitization. A few cracks ~.03 mm in width are present across the slide and filled with carbonate.
MP 9/4/2015

Specimen: 2014-080-2
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, plagioclase-feldspar, biotite, garnet, opaques, and a highly altered green mineral (likely hornblende). 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 3.6 mm (feldspar phenocryst), modal size covers a significant range from about .15 to 1.4 mm. Many of the larger quartz grains present strain induced wave extinction. Many of the smaller quartz grains may reflect strain induced nucleation. The relative amount of feldspars and quartz is difficult to estimate due to similar appearance. The only observed feldspar twinning pattern was polysynthetic, suggesting relatively few to no potassium feldspars. Stress cracks in feldspar show a preferred orientation subparallel to the long axis of the slide. Biotite is the most common mineral after quartz and feldspar with a modal size around .6 mm. There is a pronounced orientation preference with cleavage planes parallel to the thin section. Garnets are xenoblastic to hypidioblastic, up to 3.4 mm in size, and are intergrown with more common phases. Opaques are common and also present xenoblastic and hypidioblastic forms. A green mineral, likely originally hornblende, is fairly abundant but mostly transformed into a variety of alteration products, including calcite and chlorite. Feldspars show only the faintest signs of incipient weathering, with minimal sericitization along stress cracks.
MP 9/4/2015

Specimen: 2014-080-3
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, plagioclase-feldspar, biotite, garnet, opaques, and highly altered pyroxenes. Quartz and feldspar account for about 60 percent of slide area. Grains are mostly hypidioblastic with curving boundaries and random orientation. Maximum grain size is 1.2 mm (feldspar), modal size of quartz and feldspar is about .5 to .25 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. The only observed feldspar twinning pattern was polysynthetic, suggesting relatively few to no potassium feldspars. Biotite, opaques and garnet are about equally prevalent. The modal range for biotite is around .5 mm, for opaques .2 mm, and for garnet .6 mm. Garnet tends to occur in aggregates of hypidioblastic crystals. There is a pronounced orientation preference for biotite with cleavage planes parallel to the thin section. Pryoxene grains appear in a localized aggregate with individual crystals up to 1.2 mm. These pyroxenes are heavily altered into a variety of secondary minerals. Some feldspar grains present minimal sericitization, but most mineral species are relatively un-weathered.
MP 9/4/2015

Images

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Specimen ID
2014-080-1 Image of specimen in dry conditions. Finish: download image
2014-080-2 Image of specimen in dry conditions. Finish: download image
2014-080-3 Image of specimen in dry conditions. Finish: download image

Thin Sections

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Specimen ID Non-polarized Cross-polarized
2014-080-1 Specimen shown in non-polarized light.download image Specimen shown in cross-polarized light.download image
2014-080-2 Specimen shown in non-polarized light.download image Specimen shown in cross-polarized light.download image
2014-080-3 Specimen shown in non-polarized light.download image Specimen shown in cross-polarized light.download image

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

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