[Rockhounds] Newly published Agate and Jasper book

[pmodreski at aol.com]

Veva,

As to some of the equipment,

For specific gravity, I have had a "Cent-o-gram" balance, made by Ohaus, for many decades, and it gives very accurate and reproducible specific gravity readings.? It weights to +/- 0.01 gram.? I just checked online, this balance is still made, and it can be purchased for $154.50--not cheap, but it's a reliable instrument for a lifetime.

http://www.ohaus.bz/ohaus_cent_o_gram_scale.htm

Many gem testing instruments can be purchased from GIA, but their equipment is very expensive, though top quality; for example,?their dichroscope is $157 and their polariscope is $349.? I don't have any good suggestions offhand for other sources of these kinds of equipment.

I see that you can buy one of several kinds of digital refractometers for between $175 to $348 from,
http://www.mineralab.com/Gem%20ID.htm
(these of course can only be used to test polished, faceted gemstones).? I have an older model digital refractometer, a "GemMeter", which works moderately well, but it is not as accurate as a tradiational optical prism refractometer (available from GIA for $895).

Good luck!? I'm sure others will have some more advice to offer,

Pete


-----Original Message-----
From: VevaBailey at aol.com
To: rockhounds at lists.drizzle.com
Sent: Tue, 9 Jun 2009 9:40 pm
Subject: Re: [Rockhounds] Newly published Agate and Jasper book



Thank you Kreigh, for the info. 
The book is on the way!!!
Now another question for the list.
I want to purchase some testing equipment, specific gravity, polariscope,  
refractometer, etc. 
Who would the best vendor for this equipment?
I am on a limited budget, so I must get as much for my money as I can. 
My sister was out walking and brought home a piece of black, very black  
rock, it isn't lava or glass like, so I would like to test it to see if it is  
onyx, jet or jade. 
Here in Nevada, it can could be any one of these stones. I haven't  tried 
to cut it yet, so I don't know how hard it would be to cut.  



--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
---