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Chris Rayburn
Joined: 07 Oct 2013
Posts: 66
Location: Arvada, Colorado
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Posted: Aug 05, 2018 07:12 Post subject: Re: Collection Macros |
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A very simple and definitive test--place a couple of drops of vinegar on it. If it fizzes, it's calcite; if not, it's fluorite or something else.
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Oliver B
Joined: 30 Jul 2018
Posts: 27
Location: Columbus, Ohio
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Posted: Aug 05, 2018 09:24 Post subject: Re: Collection Macros |
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I will perform an acid test later today using vinegar. I have some pool based muriatic acid here that is around 30% concentration, on other samples to try and clean I mixed a 10:1 ratio of water and muriatic acid to remove calcite buildup and rust staining but what ended up happening was the crystals of fluorite in solution also began to loose their definitive edges and took on a glossy smooth appearance. I was under the impression that dilute HCL would not affect Fluorite crystals. Did i not dilute enough or would vinegar be the best solution? I have many nodules of pyrite from the area as well and wonder would the acid remove rust deposits?
Mineral: | Fluorite with Calcite |
Locality: | Ohio, USA | |
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Dimensions: | 10cm x 10cm |
Description: |
Glossy luster on the areas treated with HCL (Muriatic) |
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11502 Time(s) |
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Mineral: | Fluorite |
Locality: | Ohio, USA | |
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Dimensions: | 5cm X 5cm |
Description: |
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11517 Time(s) |
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Mineral: | Pyrite |
Dimensions: | 5cm x 5cm |
Description: |
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Viewed: |
11499 Time(s) |
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Tom Tucker
Joined: 03 Dec 2009
Posts: 60
Location: Virginia
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Posted: Aug 05, 2018 13:56 Post subject: Re: Collection Macros |
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I think the crystals in "the glossy area" are calcite that has been actively dissolved by the HCl. I don't see any fluorite. Tom
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Chris Rayburn
Joined: 07 Oct 2013
Posts: 66
Location: Arvada, Colorado
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Posted: Aug 05, 2018 15:30 Post subject: Re: Collection Macros |
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Agree, looks like acid etched calcite. Dilute HCl and vinegar should have a similar effect on calcite, although dilute HCl will generally be more aggressive. HCl should have no effect on fluorite. I've had good luck cleaning pyrite nodules with HCl, but it depends largely on what type of material is coating the pyrite. It should not harm the pyrite in any event.
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Bob Harman
Joined: 06 Nov 2015
Posts: 765
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Posted: Aug 05, 2018 15:58 Post subject: Re: Collection Macros |
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If these are all the same examples that I originally commented on, then I was correct as they look like acid etched calcite. I therefore agree with Chris and Tom. BOB
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Oliver B
Joined: 30 Jul 2018
Posts: 27
Location: Columbus, Ohio
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Posted: Aug 05, 2018 16:25 Post subject: Re: Collection Macros |
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these are separate examples. One of my apparent Fluorite specimens dissolved hard in dilute muriatic acid. It was a definite cube, which leads me to wonder if Fluorite cannot be dissolved by that solution or if calcite can grow in cubic crystal structure? the original rhombic shaped crystals are in fact fluorite, no fizz from vinegar, passed hardness tests. I will post more pictures now.
Mineral: | Fluorite |
Locality: | Alum Creek, Columbus, Franklin County, Ohio, USA | |
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Dimensions: | 1cm x 1cm (Crystal) |
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11422 Time(s) |
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Mineral: | Fluorite |
Locality: | Alum Creek, Columbus, Franklin County, Ohio, USA | |
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Dimensions: | 1cm x 1cm (Crystal) |
Description: |
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11416 Time(s) |
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Mineral: | Fluorite |
Locality: | Alum Creek, Columbus, Franklin County, Ohio, USA | |
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Dimensions: | 1cm x 1cm (Crystal) |
Description: |
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11462 Time(s) |
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Bob Harman
Joined: 06 Nov 2015
Posts: 765
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Posted: Aug 05, 2018 16:57 Post subject: Re: Collection Macros |
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In my opinion, all that you are showing are small crystals and cleavage portions of calcite. I see no fluorite! If your other example dissolved in dilute muriatic acid it also was calcite. That acid (28% HCl) specifically dissolves carbonates (including calcite) while having no effect on most non-carbonates including fluorite.
In addition.....and this can be important.....if all your specimens came from fill along a bike path along Alum Creek in Columbus Ohio, it would be statically much more likely to find pieces of calcite rather than fluorite. Calcite veins and small crystals are very common in nearby limestone, so pieces of calcite in your examples would be common while fluorite pieces would be comparatively quite uncommon making it unlikely that you found any.
OLIVER, since you seem to be enthusiastic, I suggest you join a local club and have the experienced club members help get you going. BOB
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Tom Tucker
Joined: 03 Dec 2009
Posts: 60
Location: Virginia
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Posted: Aug 05, 2018 17:01 Post subject: Re: Collection Macros |
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Your three newly posted photos show calcite only. Tom
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Jim Robison
Joined: 17 Nov 2010
Posts: 55
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Posted: Aug 05, 2018 17:33 Post subject: Re: Collection Macros |
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An important clue is the difference in shape between the two minerals. Fluorite is aa cubic mineral, which among other things mean the corners of natural crystals have a square shape or a variation on the same. Calcite is in a different crystal system, and has rhombohedral faces that are all inclined. In both minerals there are sets of parallel opposite faces, but in calcite they are inclined from the square. Fluorite always has some sets of parallel faces that are opposite but of a different orientation, but always based on the cubic oraientation. . You need to look at crystal shapes in pictures and at information on crystal shapes. I can't remember where on the Forum you find that, but believe there is a section on this topic.
As your collecting advances you will quickly discover that the form of a crystal, or a cleavage shape, is needed.
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Oliver B
Joined: 30 Jul 2018
Posts: 27
Location: Columbus, Ohio
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Posted: Aug 05, 2018 18:13 Post subject: Re: Collection Macros |
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thanks all, there isnt much to find here in columbus and i havent found any clubs or organizations locally that i can join but ill keep learning the best i can!
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Tom Tucker
Joined: 03 Dec 2009
Posts: 60
Location: Virginia
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Posted: Aug 05, 2018 19:02 Post subject: Re: Collection Macros |
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Oliver, do a web search for the Columbus Gem and Mineral Society. I'm sure you'll meet other collectors who will help you with your collecting and identification of your minerals. Tom
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Jamison Brizendine
Joined: 27 Feb 2014
Posts: 128
Location: Northeast Ohio
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Posted: Aug 06, 2018 11:57 Post subject: Re: Collection Macros |
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Hi Oliver,
I was on the road yesterday, so I just noticed this thread today. I have to agree with the others that your Alum Creek “fluorites” are also calcites, based on the physical properties. Calcite is fairly abundant in the Columbus area and has been documented on the northwest and southwest side of Columbus. Even though little geologic work has been done on the northeast or southeast side of the city, I wouldn’t doubt you could find calcite crystals on that side as well.
The closest documented fluorite locality near you is the National Lime & Stone Co. Delaware Quarry (frm. The Klondike Quarry), north of Bellepoint in Scioto Township. The fluorite was collected in the Columbus and Delaware Limestone formations at the extreme southeast corner of the Findlay Arch. I don’t think collectors have been granted access to that quarry and fluorite is fairly rare there.
Since you live in Columbus, I would also recommend you join and show your specimens with the Columbus Rock and Mineral Club. They are a fairly active club that puts on a mineral show every year in the beginning of April. Finally, I would recommend also picking up a copy of Ernest Carlson, Minerals of Ohio. The second edition of the book is the current (2015) edition and is updated.
Glad to know there are more enthusiastic Buckeye State collectors and looking to seeing new things you are finding.
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