Bill Aycock on sun 15 jul 01
I cant resist a good play on words, even in a persons name.- It is very
fitting that a potter with a name that means "green mountain" be discussing
the properties of a green mineral.
Bill
At 01:42 PM 7/15/01 -1000, you wrote:
>When the wind and waves are right, the beaches near here on east Oahu
>go completely green from olivine. Some beaches on the Big Island are
>almost pure olivine all the time.
>
>I've heard of this sand being included in high fire glazes, but I'm
>not sure what it does - stays green or fluxes out into something else?
>
>- Rick Monteverde
>Honolulu, HI
-
Bill Aycock --- Persimmon Hill
Woodville, Alabama, US 35776
(in the N.E. corner of the State)
W4BSG -- Grid EM64vr
baycock@HiWAAY.net
w4bsg@arrl.net
Joseph Herbert on sun 15 jul 01
Guessing the green/yellow bits are the mineral olivine. I have seen a
basalt "bomb" - football shaped thing that was thrown through the air by the
volcano, that was entirely a mass of olivine crystals on the inside. The
mineral is transparent, green, and has a conchoidal fracture. The
composition ranges from magnesium silicate to iron silicate in a continuous
solid solution series. This mineral is kind of heavy - Specific gravity
ranging form just over 3 for the Magnesium version (forsterite) to just over
4 for the iron version (fayalite).
This material is marketed as peridot in the jewelry trade. Its hardness is
only 6.5 to 7, scratched by quartz, low for an item to wear.
Joseph Herbert
Rick Monteverde on sun 15 jul 01
When the wind and waves are right, the beaches near here on east Oahu
go completely green from olivine. Some beaches on the Big Island are
almost pure olivine all the time.
I've heard of this sand being included in high fire glazes, but I'm
not sure what it does - stays green or fluxes out into something else?
- Rick Monteverde
Honolulu, HI
>Guessing the green/yellow bits are the mineral olivine. I have seen a
>basalt "bomb" - football shaped thing that was thrown through the air by the
>volcano, that was entirely a mass of olivine crystals on the inside. The
>mineral is transparent, green, and has a conchoidal fracture. The
>composition ranges from magnesium silicate to iron silicate in a continuous
>solid solution series. This mineral is kind of heavy - Specific gravity
>ranging form just over 3 for the Magnesium version (forsterite) to just over
>4 for the iron version (fayalite).
>
>This material is marketed as peridot in the jewelry trade. Its hardness is
>only 6.5 to 7, scratched by quartz, low for an item to wear.
>
>Joseph Herbert
>
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