Nuummit Ring / Cabochon / new- 6.35 g - (1)

Ring Nuummit / Cabochon / new

Set in 925 sterling silver

New and unworn

Weight: 6.35 g

20.7 mm x 14.7 mm

New and unworn

Ring size:

EU 54 - 55 (sits right in between)
UK N - O
US 7.0
FR 14 - 15
Inner diameter: 17.35 mm

Nuummite, also Nuummite, is a rare metamorphic rock mainly composed of the minerals gedrite and anthophyllite. The name derives from the Nuuk locality in Greenland.
The base color is almost black and often iridescent due to inclusions; the rock is opaque. In addition to the two amphiboles gedrite and anthophyllite, pyrite, pyrrhotite and chalcopyrite occur as accessory minerals. The two amphiboles form a twin lamellation created by exsolution in the solid state, and in cut specimens are characterized by a yellow-gold iridescence.

The originally magmatic rock, after its formation in the Archean about 2.8 Ga (billion years ago), geologically a short time later—in about 2.7 Ga and 2.5 Ga—underwent at least two metamorphic events, and is today referred to as ortho-amphibolite.

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