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Dolph Pond Granite

Submitted by Ed FitzGerald on Tue, 2015-01-13 14:43
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
Stone Type (Lithologic): 
Grain Shape: 
Angular
Subangular
Grain Size: 
Very Coarse
Medium
Petrographic Description: 

Specimen: 2014-083-1
This sample is likely a metramorphosed plutonic rock composed of xenoblastic and hypidioblastic grains. The crystalline structure is coarse with minimal foliation. Maximum crystal dimension is 14 mm (quartz). Several large phenocrysts occupy a significant portion of the slide. The remaining mineral assemblage has a modal size range from about 1.4 to .4 mm. Relative quartz and feldspar contributions are difficult to estimate due to the impact of large phenocrysts and overall similar physical appearance, excluding the large quartz porphyroblasts, feldspar would predominate. Feldspar twinning is not common but polysynthetic examples are present. Rare micrographic quartz-feldspar intergrowths are also visible. All non quartz-biotite minerals occupy about 25 to 30 percent of slide area. These accessory minerals occur most often in aggregates. Biotite is the most common accessory mineral and occupies about 5 to 10 percent of slide area in a patchy distribution. Biotite has a preferred orientation parallel to the slide surface. Garnet is present at about 5 percent of slide area and a maximum crystal size of 4.4 mm. Opaques are also common; muscovite is present in trace amounts. There are several areas containing alteromorphs of mafic minerals. These are now near wholly altered to serpentine and other secondary products such as chlorite and likely talc and others. Feldspars also present low to moderate amounts of sericitization. The clustering of non-quartz/feldspar minerals produces visible structure in both the thin section and in hand sample.
MP 9/4/2015

Specimen: 2014-083-2
This is a metamorphic rock composed of xenoblastic and hypidioblastic grains. The crystalline texture is coarse. Maximum crystal dimension is 8 mm (quartz). The slide is dominated by large porphyroblasts with a modal size around 5 mm. The finer grained ground mass of quartz and feldspar has a modal grain size around 1.2 to .4 mm. Feldspars appear to predominate over quartz, but the minerals are hard to distinguish due to visual similarity. Polysynthetic twinning predominates in feldspars. Polygonal equigranular grain textures are locally common. Most boundaries are curved or sutured. Wave extinction is common in quartz, but there is little evidence for grain nucleation. Non-quartz/feldspar minerals occupy about 40 percent of slide area. Xenoblastic to hypidioblastic garnet, with a maximum dimension of 8 mm, is the most abundant at about 30 percent of slide area. Biotite and opaques are also common at about 5 percent of slide area apiece. Epidote and muscovite are present in trace amounts. Secondary carbonate and other alteration products occur in association with garnet and the other accessory minerals, suggesting more mineral species may have once been present. Moderate to minimal sericitization of feldspars is also ubiquitous.
MP 9/4/2015

Specimen: 2014-083-3
This is a metamorphic rock composed of xenoblastic and hypidioblastic grains. The crystalline texture is coarse. Maximum crystal dimension is 5 mm, the modal size is about 1.6 to .4 mm. Feldspar is more common than quartz, but quartz is more often present as larger porphyroblasts. Together quartz and feldspar comprise approximately 50 percent of slide area. Polysynthetic twinning predominates among feldspars. Most boundaries are smooth with a lesser amount of sutured. Wave extinction is common among quartz and some grain nucleation appears to have occurred. The most common accessory mineral is garnet, which appears as xenoblastic to hypidioblastic crystals up to 12 mm in maximum dimension. Garnet occupies about 20 to 30 percent of slide area. Biotite is also abundant at about 15 to 20 percent of slide area. The deep red color of the biotite may suggest significant titanium presence. Opaques are also common at around 5 percent of slide area. Epidote and muscovite are present in trace amounts. There is a localized area of other mafic minerals, likely pyroxenes and olivine, that are now heavily weathered into a variety of secondary minerals: calcite, chlorite, and others. These areas are associated with garnet and biotite aggregates. Feldspars also show appreciable sericitization.
MP 9/4/2015

Specimen: 2014-083-4
This is a metamorphic rock composed of xenoblastic and hypidioblastic grains. The crystalline texture is coarse. Maximum crystal dimension is 12.4 mm. There is a bimodal distribution of grains, large porphyroblasts with a mode around 4.4, and a finer grained component near .9 mm. Most of the porphyroblasts are qurartz and this mineral appears to predominate over feldspar, but it is difficult to estimate the relative contributions due to similar visual appearance. Together quartz and feldspar comprise approximately 70 percent of slide area. Polysynthetic twinning predominates among feldspars. Most boundaries are smooth with a lesser amount of sutured. Wave extinction is common among quartz and some grain nucleation appears to have occurred. The most common accessory mineral is garnet, which appears as subhedral to anhedral crystals up to 5.2 mm in maximum dimension. Garnet occupies about 20 percent of slide area. Biotite is also abundant at about 5 percent of slide area. The deep red color of the biotite may suggest significant titanium presence. Opaques are also common at around 1 to 3 percent of slide area. Epidotes are present in trace amounts. Feldspars show appreciable sericitization.
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

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