What is assay glass.

  Assay glass is a subsequent effect and a by product of a method used to assess a certain location for gold propectives - a method no longer employed.....This particular glass originated from a gold mine in Utah referred to as Mercer Mines.....the specimans available here were collected by a elderly gentleman approxiamatley 30 - 40 years ago and come in different shades of color mainly a yellow gold and green as well as translucent and solid...Certain field test were applied to this material in order to ascertain a rating on the mohs hardness scale and as according to the field test applied the mohs rating relative to such is a grade of approxiamatley 3.0 - 5.5 ....(field test as derived from "complete book of rocks, gems and minerals copyright 1968 by Peterson publishng company.). As according to information gathered the glass was highly prized by people of the faceting community who targeted this mine and collected most of this by product before that particular mine was filled in...rendering this particular item and merchandise as being rare and not readily available in it's status amongst rare gem material...Although referred to as a glass the texture and consistency seem to be more in line with that of an Oregon sunstone and beryl type of material....Although not a natural material in terms of being a natural growth subsequented by good ole mother nature it is never the less an item that could very well be considered as being a collectors item and a rare gem due to the absence of the subsequent which led to it's creation and the likley hood that this particular material will never again be available...currently as of 10-08-2015 lab created gems average approxiamatley $3.57 per gram with actual prices ranging from 9.87 per gram to .16 per gram and in that the intent of this particular material was not that of a gem stone as such but is indeed a by product of another process a classification within that field would seem to be out of place so rather than treat it as such emphasis was otherwise placed on the rarity and quality of the item in accordance with the factors mentioned above and was rated accordingly within a category sufficient for it's relation within the expanse of the rare gem material criteria currently reffered to as "rare facet grade rough" as mandated by the search criteria utilized to assess the cmv of facetable grade rare gem stones to include:

1. Tanzanian Pink Rhodalite at $77.08 per gram when purchased in 1.30 gram lots.
2. Nigerian tourmaline at $50.00 + per gram when purchased in1.91 gram lots.
3. Green emerald - I have seen quality faceted stones as high as $14,000.00 per carat when purchased in 4.96 carat lots.
4. Green moldavite at $30.81 per gram when purchased in 13.0 gram lots.
5. Chrome diopside at $15.00 gram when purchased in 1.0 gram lots..
6. Etc.

Keeping in mind that all of the above mentioned material are to certain extents still available and mined...Although not a professional in the faceting field in my opinion not to mention the popularity of such amongst facetors 20-30 years ago - this material would make a quality gemstone with a brilliance limited only by the expertise of the facetor/lapidarist at work if not just a collector's speciman of a material that could be no longer available and that could very well be considered as being a treasure and is as mentioned currently unique to this source alone and is the main material we market in our raw gem department...

Available quantity: apprx. 8lbs
Estimated value: As acquired Utilizing the low end of the estimated value of the rare facetable gem criteria and the current market value(cmv) of lab created gems also considering the comparable quality and availability of a finished stone of other facetable material placing the estimated value lower than the low end of rare and other natural facetable material but in excess of the current market value of lab created gems summizing to an estimated current value of apprx.$4.57 per gram and possibly more with emphasis placed upon the rarity of the material...

  • Note: cmv subject to change in accordance with the speculative factors utilized.
  • Note: speculations do not include any guarantees in price fluctuations.
  • Note: cmv listed is not the representation of any standard that may be correspondent with the semi precious minerals market or any other reasonable facsimile thereof but are as compiled by an independent operating facility utilizing the factors described under "estimated value" with the intent and objective of ascertaining a comprehensive current market value that would correlate with the current condition/conditions of the relative mineral/material and should be fairly close if not accurate to the measurement of the current market value that may correspond with any standards relative to the semi precious minerals market/industry and is introduced soley as a means at which to perpetuate to the prospective investor/customer a basic value necessary with investment decisions..
  • Note:
  • The venture"Wayne R. Butler Enterprises" shall not be held liable for any deviations away from the facetors/lapidarist/others objective/objectives due to raw gem material consistency or stability...all discretions relative to such are the sole responsibiltiy of the purchaser and/or the party hired to accomplish such objective.

    Shipping discounts apply..size and weight limitations apply approxiamatley 20lbs per box...Total purchase must be equal to or exceed a total shipping cost of $12.95 any shipping cost in excess of that amount will be discounted accordingly to not exceed a total shipping cost of $12.95.. .

    Assay process:

    Fire assaying is the oldest and most reliable method of determining gold and silver in rock or concentrate samples. This method is still the industry standard. It is called ''fire'' assay because it involves smelting the sample which has been mixed with lead oxide. Until electric furnaces were available, samples were smelted literally in a fire.

    Six steps
    There are six steps in the fire assay procedure: splitting - weighing - mixing firing - cupelling - parting.

    First, the crushed and ground sample of ore or concentrate is carefully split down to a smaller and, one hopes, representative sample. This is usually done using a riffle splitter. Finally a small sample of only around 30 grams is weighed out and added to a crucible. To this is added a mixture of lead oxide, a reducing agent and fluxes. The fluxes usually consist of silica sand, borax and sometimes additional additives like fluorite. The fluxes, reductant, lead oxide and sample are then mixed and fired in a, muffle furnace.

    In the furnace the complete contents of the crucible are melted. In the presence of the reducing agent, typically carbon in any form, e.g. flour, the lead oxide is smelted to lead metal which "collects" any silver and gold that may have been in the sample. The molten mass is taken from the furnace and swirled to mix before being poured into a cone-shaped mold and allowed to cool. The molten lead sinks to the bottom of the mold, carrying any gold and silver with it, while the rest of the components of the ore along with the flux turn into a glassy slag that floats on top of the mold.

    After cooling, the metallic lead "button" at the bottom of the mold is separated from the glassy slag which is discarded.

    The metallic lead button is placed into a cupel, which is a small dish made from bone ash, and placed into a cupelling furnace. In the "cupelling" process lead metal turns back into oxide which volatilizes away from the precious metals and soaks into the bone ash cupel, leaving the minute amount of precious metals as a metallic speck of metal called a "bead" on the bottom of the cupel.

    Next, the bead is weighed on a microbalance to determine the amount of gold and silver that was extractable from the original ore sample. The bead is next heated in hot nitric acid which dissolves away the silver, leaving any gold that may have been present. This step is called "parting" because the nitric acid "parts" the gold from the silver-gold mixture in the bead.

    The parted bead is then carefully weighed and this amount of gold is related back to the weight of ore or concentrate sample in the first crucible that was fired.

    In more modern laboratories, the bead of precious metals that is recovered in the cupel after the lead has been removed is dissolved in aqua regia. The resulting solution is then analyzed by atomic absorption spectrometry, allowing the grade of gold and silver in the original sample to be back calculated.

    Is the fire assay sample big enough? The problem with fire assaying is not with the method itself, but rather with the sample size that is used. Fire assaying generally uses about one "assay ton" of pulverized sample, i.e. 29.84 grams of material.

    If much of the gold occurs in a deposit as small "nuggets", then the chance of the assay ton sample's being representative is remote. If even one of the smallest nuggets or particles of visible gold gets into the small sample that is fire assayed, then the result will be incredibly high. On the other hand, if none of the minute gold particles in the ore get into the assay ton that is fire assayed, then the assay result is likely to be lower than reality.

    Fire assaying is a science, and also to some extent still an art. Certain types of ore contain elements that may interfere with the result. A good fire assayer knows how to modify the composition of the flux to avoid these problems.

    The fire assayer knows how to determine the gold and silver content of the assay ton of sample that has been presented to him or her. The big question is whether that assay ton is truly representative of the sample of core that it came from, and whether the core sample itself is truly representative of the ore deposit from which it came.

    Buy your "pet rock" today it may prove to have positive returns in the future..thank you

    Copyrightę2015 correspondence-etc.com all applicable copyright statutes apply.