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min data

Mineral: quartz
Gem: graveyard point plume agate (cryptocrystalline)
Size: 27x32 mm & 20x42 mm & 34x46 mm
& 25x65 mm & 37x50 mm & 34x52 mm
Carat: 49.6 ct & 48.2 ct & 71+ ct
& 85+ ct & 112+ ct & 112+ ct
Cut: cabochon
Origin: Oregon - Idaho
General Info: Agate (achates) was named from the river Achates, now the Drillo, in Sicily, where the stone was first identified. It is cryptocrystalline quartz (micro crystals) usually with a banded pattern (although not always).
Additional Information
Graveyard point plume agate comes from the Owyhee Mtns. along the Oregon - Idaho border. It is a seam agate and found near the same location that regency rose plume agate originates.

All of these stones cut by the author. The framed stones are framed with black agate (no backing). Many of the graveyard point plume agates have metallic looking marcasite (most easily seen in the two framed stones as the metallic sparkles in the top of each stone). The plumes can be white, tan, orange, gray, cream, or even yellow to greenish.

Since a single stone may contain a variety of different plumes, it is not unusual for some plumes (depending on their chemistry) to cut at different rates. Hence this material is subject to some undercutting. The stone may also contain fracture lines and crystalline vugs. The bottom two stones are backed with a nearly clear agate as they contain discontinuous fractures.

The metal component appears to be marcasite.

White plume in graveyard point Multicolor plumes in graveyard point.
Marcasite plumes in graveyard point. Multicolor plumes in graveyard point.