Guest guest Posted June 10, 2005 Report Share Posted June 10, 2005 Dear Sir, Nice post. From what I've heard, Orthoquartzite is a pure quartz sandstone, with less than 5 percent contaminant, that has not been metamorphosed. Quartzite is metamorphosed orthoquartzite, which is basically recrystallized as there's not much else you can do to a pure SiO2 substance. Therefore, by extension, a Metaquartzite must be a metamorphosed quartzite. Many people refer to quartzite when they are talking about a metamorphosed sandstone (of high, though unspecified quartz content). However, a quartzite does not have to be recrystallized, just cooked and well-indurated. Highly deformed quartzite can be refered to as quartzite mylonite, if it contains the proper textures. One disclaimer here... my " metaquartzite must be a metamorphosed Quartzite " might not really stand scrutiny; it could well be a twice-metamorphosed orthoquartzite. But hey, there's only so much that one can recollect off a subject studied for about 4 hours, 20 years ago J Respects, Ramapriya ayirpamar On 6/10/05, yobrevol <yobrevol wrote: Namaste All, In this mail I write to you a little about one family of stones called Quartz, I apologize for being long overdue in this mail, but Vegas gem show occupied my time. It is a common mineral from which many different types of rocks and gems come from, chemically a quartz is basically silicon oxide. On mohs' scale it comes up to about 7 , if I recall correctly. Now, quartzite is akin to a sandstone but only metamorphosed ( recall three types of rock formations from elementary science classes:- sedimentary, metamorphic, and igneous). The metamorphosis is both in reference to mineral composite and texture is non-foliated in nature( like marble as oppose to slate). I believe that these are much harder than regular quartz because of greater concentration of quartz in it, resulting in more compressed hardening. Perhaps this is a factor as to why quartzite's break through producing smooth polish surface as oppose to rough and granular likes you get in common quartz's. Most commonly found gems in the semi-precious category of colorstones coming out of the quartz family are : citrine, lemon (or oro verde), champange, rose, smokey (brown, black, or lemon brown), white crystal and of course, the amethyst. Recently, a green amethyst is also being produced which is basically very pale green pastel color quartz. If these colors are occurring naturally ( since its easy to cook most of quartz to switch colors), it is basically the result of impurities present in the rock at the time of formation. Having said that, I would ask the learned to correct me; also, I can write more on this and related topics, if anyone wants to know in detail. namaste; Gaurav Jain Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 10, 2005 Report Share Posted June 10, 2005 Jaya Jagannatha Dear Rama and Gaurav, Namaste Nice posts. Can you be more specific and give a more complete list of gemstones from the quartzite family? Gaurav, what colours the amethyst green? Then we can begin discussions with quotes from the Purana………. Love, Swee On Behalf Of Ramapriya D Friday, June 10, 2005 4:15 PM Re: [Jaya Jagannatha] quartzites introduction... Dear Sir, Nice post. From what I've heard, Orthoquartzite is a pure quartz sandstone, with less than 5 percent contaminant, that has not been metamorphosed. Quartzite is metamorphosed orthoquartzite, which is basically recrystallized as there's not much else you can do to a pure SiO2 substance. Therefore, by extension, a Metaquartzite must be a metamorphosed quartzite. Many people refer to quartzite when they are talking about a metamorphosed sandstone (of high, though unspecified quartz content). However, a quartzite does not have to be recrystallized, just cooked and well-indurated. Highly deformed quartzite can be refered to as quartzite mylonite, if it contains the proper textures. One disclaimer here... my " metaquartzite must be a metamorphosed Quartzite " might not really stand scrutiny; it could well be a twice-metamorphosed orthoquartzite. But hey, there's only so much that one can recollect off a subject studied for about 4 hours, 20 years ago J Respects, Ramapriya ayirpamar On 6/10/05, yobrevol <yobrevol wrote: Namaste All, In this mail I write to you a little about one family of stones called Quartz, I apologize for being long overdue in this mail, but Vegas gem show occupied my time. It is a common mineral from which many different types of rocks and gems come from, chemically a quartz is basically silicon oxide. On mohs' scale it comes up to about 7 , if I recall correctly. Now, quartzite is akin to a sandstone but only metamorphosed ( recall three types of rock formations from elementary science classes:- sedimentary, metamorphic, and igneous). The metamorphosis is both in reference to mineral composite and texture is non-foliated in nature( like marble as oppose to slate). I believe that these are much harder than regular quartz because of greater concentration of quartz in it, resulting in more compressed hardening. Perhaps this is a factor as to why quartzite's break through producing smooth polish surface as oppose to rough and granular likes you get in common quartz's. Most commonly found gems in the semi-precious category of colorstones coming out of the quartz family are : citrine, lemon (or oro verde), champange, rose, smokey (brown, black, or lemon brown), white crystal and of course, the amethyst. Recently, a green amethyst is also being produced which is basically very pale green pastel color quartz. If these colors are occurring naturally ( since its easy to cook most of quartz to switch colors), it is basically the result of impurities present in the rock at the time of formation. Having said that, I would ask the learned to correct me; also, I can write more on this and related topics, if anyone wants to know in detail. namaste; Gaurav Jain Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 11, 2005 Report Share Posted June 11, 2005 Jaya Jagannatha Dear List, Namaste I see no takers on this and will proceed with the family of the quartzite family. The quartz family include (gem) stones of the following: Citrine, amethysts, rock crystal, smky quartz, prasiolite, rose quartz, aventurine, blue quartz, quartz cat’s eye, hawk’s eye, tiger’s eye, chalcedony, cornelian, sard, chrysopase and matrix, heliotrope, moss agate (also had a mention in the Purana), dentritic agate, agate, jasper (brown/brownish red), petrified wood and opals. The rest later J Love, Swee On Behalf Of Swee Chan Friday, June 10, 2005 5:52 PM RE: [Jaya Jagannatha] quartzites introduction... Jaya Jagannatha Dear Rama and Gaurav, Namaste Nice posts. Can you be more specific and give a more complete list of gemstones from the quartzite family? Gaurav, what colours the amethyst green? Then we can begin discussions with quotes from the Purana………. Love, Swee On Behalf Of Ramapriya D Friday, June 10, 2005 4:15 PM Re: [Jaya Jagannatha] quartzites introduction... Dear Sir, Nice post. From what I've heard, Orthoquartzite is a pure quartz sandstone, with less than 5 percent contaminant, that has not been metamorphosed. Quartzite is metamorphosed orthoquartzite, which is basically recrystallized as there's not much else you can do to a pure SiO2 substance. Therefore, by extension, a Metaquartzite must be a metamorphosed quartzite. Many people refer to quartzite when they are talking about a metamorphosed sandstone (of high, though unspecified quartz content). However, a quartzite does not have to be recrystallized, just cooked and well-indurated. Highly deformed quartzite can be refered to as quartzite mylonite, if it contains the proper textures. One disclaimer here... my " metaquartzite must be a metamorphosed Quartzite " might not really stand scrutiny; it could well be a twice-metamorphosed orthoquartzite. But hey, there's only so much that one can recollect off a subject studied for about 4 hours, 20 years ago J Respects, Ramapriya ayirpamar On 6/10/05, yobrevol <yobrevol wrote: Namaste All, In this mail I write to you a little about one family of stones called Quartz, I apologize for being long overdue in this mail, but Vegas gem show occupied my time. It is a common mineral from which many different types of rocks and gems come from, chemically a quartz is basically silicon oxide. On mohs' scale it comes up to about 7 , if I recall correctly. Now, quartzite is akin to a sandstone but only metamorphosed ( recall three types of rock formations from elementary science classes:- sedimentary, metamorphic, and igneous). The metamorphosis is both in reference to mineral composite and texture is non-foliated in nature( like marble as oppose to slate). I believe that these are much harder than regular quartz because of greater concentration of quartz in it, resulting in more compressed hardening. Perhaps this is a factor as to why quartzite's break through producing smooth polish surface as oppose to rough and granular likes you get in common quartz's. Most commonly found gems in the semi-precious category of colorstones coming out of the quartz family are : citrine, lemon (or oro verde), champange, rose, smokey (brown, black, or lemon brown), white crystal and of course, the amethyst. Recently, a green amethyst is also being produced which is basically very pale green pastel color quartz. If these colors are occurring naturally ( since its easy to cook most of quartz to switch colors), it is basically the result of impurities present in the rock at the time of formation. Having said that, I would ask the learned to correct me; also, I can write more on this and related topics, if anyone wants to know in detail. namaste; Gaurav Jain Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 14, 2005 Report Share Posted June 14, 2005 Hare Rama Krishna, Namaste, I think pisolith is what is specific about green amethyst; if naturally occurring, it contains relatively higher degree of calcium carbonate. Of course, most of my exposure is to the cooked one (in fact i am currently cutting some briollets out of it). Swee Ji can guide us further. Namaste; Gaurav Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 14, 2005 Report Share Posted June 14, 2005 Hare Rama Krishna, Namaste swee ji, Are we saying all opals are quartzites? I mean given the amount of water they have....and the weight ( or the lack of it)... Please educate; gaurav Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 15, 2005 Report Share Posted June 15, 2005 Jaya Jagannatha Dear Gaurav, Namaste I gave you a hint J prasiolite is leek green. This is done by heating amethyst and yellow quartzes (from Minas Gerais) to get that colour……….can be confused with Beryl. Agree? Love, Swee On Behalf Of yobrevol Wednesday, June 15, 2005 12:06 AM Re: [Jaya Jagannatha] quartzites introduction... Hare Rama Krishna, Namaste, I think pisolith is what is specific about green amethyst; if naturally occurring, it contains relatively higher degree of calcium carbonate. Of course, most of my exposure is to the cooked one (in fact i am currently cutting some briollets out of it). Swee Ji can guide us further. Namaste; Gaurav Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 16, 2005 Report Share Posted June 16, 2005 Hare Rama Krishna, Namaste Swee Ji, I gave you a hint J prasiolite is leek green. This is done by heating amethyst and yellow quartzes (from Minas Gerais) to get that colour……….can be confused with Beryl. Agree? The color can easily be confused with pale green beryl. Do you know where does it occur in its natural form? would imagine somewhere near hot-springs or enraptures zones... The GIA calls it Praseolite. Do you know what is sagenitic (quartz) ? Also, I think aventurine probably should also be classified as a quartz. Some agates i thought, including moss agate, dendritic agate, fire agate, chrysophrase and onyx, sardonyx were also classified as "quartz chalcedony".... Namaste Gaurav Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 16, 2005 Report Share Posted June 16, 2005 Hare Rama KrishnaNamaste, I have yet to see some cats eye clear quartz. May I request you to throw some light on the use and effect of "cats' eye" stones in jyotish. paparadscha -I know that is mined in Lanka, but do not know more on it. Marble, I have seen the mine during last visit to India, My wifes' relatives are largest miners in the world of marble, they are marketing the copper and pale yellow/creamish marble as Wonder marble. Namaste,Gaurav Jain Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 16, 2005 Report Share Posted June 16, 2005 Jaya Jagannatha Dear Gaurav, Namaste GIA’s spelling is wrong. Prasiolite is correct. The crystal is hexagonal trigonal shape. Do you have Webster’s Read? I have the 5th edition. Expensive book, but you should treat it as your Bible J What I queried was the copper coloured marble within the confines of a sapphire mine. Like it’s quite normal to find spinel etc alongside. The fact that schist (black tourmaline is there, should be sufficient to identify this particular gemmy marble. Like at my mine, you’ll find tourmaline, eroded spessartite, quartz (smoky) and some interesting gemmy white marble, which people mistake for pegmatite. Though there is a report of a likely diamond find, I have not yet endeavoured that part. The cat’s eye mentioned in Garuda Purana the cat’s eye emits fine colours of the rainy season. Gems shoot off flames as it were in tune with the shrill cry of Bala asura. Later, it states that the outer colours of the blue jay bird are not approved of by experts in technical literature, though the vibrant green is mentioned. Alexandrite is the most probable in the colour change gemstone. The chief of them is the blue and changes to red in artificial light. This has definitely narrowed down most things for Vaidurya. The crystallization of Chrysoberyl seems the most conclusive, being orthorhombic with inter-grown triplet (crystals) and hardness is 8.5. Garuda Purana Chapter 73.8 tells us that the Girikaaca is spurious – eight sided like tortoise shell like luster and brilliancy is ropey (the silky striations). There are many hexagonal crystals and this includes the beryl family. The other word, I am yet to decipher – shishupaala – any idea? Could be (eroded) quartzite from the description. What do you think of the colour change garnet as an uparatna? The alexandrite is way out of people’s pockets. Talking of which, it might have been 1994 when I the decisive reclassifications of PRECIOUS versus SEMI PRECIOUS gemstones came about since Argle Diamonds began producing coloured diamonds in profusion (another cartel to kill us with prices J) So it is to be known as such : Diamonds and Colour Gemstones. Period. Wearing the Vaidurya bring good luck to the wearer. The reticulated needles enmeshed in a rock crystal gives the sagenitic quartz. This is totally to be discarded. Love, Swee On Behalf Of yobrevol Thursday, June 16, 2005 4:45 PM Re: [Jaya Jagannatha] quartzites introduction... Hare Rama Krishna, Namaste Swee Ji, I gave you a hint J prasiolite is leek green. This is done by heating amethyst and yellow quartzes (from Minas Gerais) to get that colour……….can be confused with Beryl. Agree? The color can easily be confused with pale green beryl. Do you know where does it occur in its natural form? would imagine somewhere near hot-springs or enraptures zones...The GIA calls it Praseolite. Do you know what is sagenitic (quartz) ? Also, I think aventurine probably should also be classified as a quartz. Some agates i thought, including moss agate, dendritic agate, fire agate, chrysophrase and onyx, sardonyx were also classified as " quartz chalcedony " .... Namaste Gaurav Quote Link to comment Share on other sites More sharing options...
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