Porphyry Island is an

island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island ...

in Unorganized

Thunder Bay District Thunder Bay District is a district and census division in Northwestern Ontario in the Canadian province of Ontario. The district seat is Thunder Bay. In 2016, the population was 146,048. The land area is ; the population density was . Most ...

in northwestern

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. It is the last island in a chain stretching south west of the

Black Bay Peninsula Black Bay Peninsula is a volcanic peninsula in Unorganized Thunder Bay District in Northwestern Ontario, Canada, located on the North Shore of Lake Superior. Shows the extent of the peninsula highlighted on a map. It separates Black Bay and Nip ...

Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...

. It is located about from Edward Island Provincial Park, from

Sleeping Giant Provincial Park Sleeping Giant Provincial Park, established in 1944 as Sibley Provincial Park and renamed in 1988, is a park located on the Sibley Peninsula in Northwestern Ontario, east of Thunder Bay. The nearest communities are Pass Lake, in the township o ...

, east of

Silver Islet, Ontario Silver Islet refers to both a small rocky island and a small community located at the tip of the Sibley Peninsula in northwestern Ontario, Canada. A rich vein of pure silver was discovered on this small island in 1868 by the Montreal Mining ...

, and east of the city of

Thunder Bay Thunder Bay is a city in and the seat of Thunder Bay District, Ontario, Canada. It is the most populous municipality in Northwestern Ontario and the second most populous (after Greater Sudbury) municipality in Northern Ontario; its population i ...

. The island and nature reserve take their name from the characteristic

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

and

feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) felds ...

crystals, or

porphyries Porphyry ( ) is a textural term for an igneous rock consisting of coarse-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate-rich, generally aphanitic matrix or groundmass. The larger crystals are called phenocr ...

found in the volcanic rocks. The entire island constitutes the Porphyry Island Provincial Park or nature reserve.

Point Porphyry Lighthouse

The federal government established a lighthouse at Point Porphyry in 1873. This is located at the southwestern tip of the island.

References

Sources

* * {{refend Landforms of Thunder Bay District Uninhabited islands of Ontario Islands of Lake Superior in Ontario