What's the difference between greenstone and poenamu?

Greenstone

Definition:

(n.) A name formerly applied rather loosely to certain dark-colored igneous rocks, including diorite, diabase, etc.

Example Sentences:

(1) The root surfaces apical to the overhangs were photographed under the scanning electron microscope at a magnification of x 140 and compared by five dentists, in a single-blind manner, with two control photomicrographs of surfaces classified as rough (treated with a coarse diamond bur) or not rough (treated with a greenstone).
(2) Yet according to Michael Greenstone, an economics professor at MIT and one of the study's authors, this study is the first to precisely quantify their relationship.
(3) Take a seaplane to Rock Harbor or Windigo and follow the Greenstone Ridge Trail, a 40-mile hike along the spine of the island, which takes four or five days.
(4) The North Island is Te Ika A Maui, "the fish of Maui" (recounting the mythic tale of New Zealand's creation) where the South is Te Wai Pounamu, "the waters of greenstone" (describing the glassy stone, prized by Maori, that is found in the swift rivers and along the savage misted beaches of the lonely south).
(5) Contact +1 305 242 7700 for a permit application Jeremy Cuff, underwater photographer and contributor to Sport Diver magazine Greenstone Ridge Trail, Isle Royale NP , Michigan Isle Royale is a roadless archipelago in Lake Superior on the Canadian border.