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Post by fernwood on Aug 20, 2018 17:22:23 GMT -5
Found these in the Rock Shed clearance section. Added them to my order. Selenite will dissolve in water, so they are specimen pieces only. Not really suitable for lapidary work. They are a little over 7” tall. Are on my fireplace mantle now. Plan to leave them there until winter. Also use as display pieces at shows. The true color is pure white. Camera flash caused the darker areas. They have vertical fibers. Reflect a lot of light and absorb/reflect the color of anything near them. For the animal lovers out there. Yes, the shadow you can see through the window is my barn cat, Spot I love them. Have always wanted some Selenite.  1  2 |
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Post by MsAli on Aug 20, 2018 17:50:56 GMT -5
I have selenite all over my house. Have the coolest palm stone from it also that I use for meditation
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Post by vegasjames on Aug 20, 2018 18:30:14 GMT -5
First of all those are not selenite they are satin spar frequently mislabeled as selenite. Selenite is a clear version of gypsum. Satin spar is the smaller fibrous, translucent version of gypsum.
They will dissolve in water if left in water literally for years. I wash my selenite crystals in water multiple times to get most of the mud off then actually boil them in water to help get mud out of the nooks and crannies. Sometimes I soak them for months. Never had a crystal dissolve yet. Again it literally takes years to dissolve.
I have also cabbed a number of pieces of selenite and they make very cool cabs. I would not recommend it for rings since they will easily get banged up but can be used for necklaces. The trick to cabbing selenite crystals is to not be aggressive with them on the first wheels. I generally start the 2nd to third wheel over. Gently round over the edges first when cabbing. The crystals grow in plates and if a sharp edge catches the wheel it will split the crystal. So by gently rounding off the edged first this eliminates any sharp edges that can catch the wheel and split it. When shaped and finished with the last wheel buff the crystals with a buffing wheel with a little Zam which seals the crystals and gives it a beautiful luster.
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Post by vegasjames on Aug 20, 2018 18:32:08 GMT -5
Here is my write up I did on the different forms of gypsum. Clearing Up the Confusion About Forms of Gypsum. There seems to be a lot of confusion over the different forms of gypsum, which in particular is leading to the mislabeling of satin spar for selenite. So I figured I would write this to clear up the confusion. I really like gypsum because of its ability to form in so many shapes. I have collected crystals that look like angle wings, diamonds, one that looked like a bunch of little pentagons stacked on each other, some that look like fish skulls, blades, fish tails, swallow tails, hourglasses, crowns, etc., etc. etc. It also comes in different colors. I have been mining red selenite for years and have also found a deposit of golden selenite, and found one piece of green selenite and an interesting piece of gypsum that was root beer colored. Close by here is a humongous deposit of brown gypsum, some of which is as selenite. And occasionally I can find the clear “white” gypsum commonly referred to as “Utah glass”. Sometimes I find the selenite in clusters or as crystals growing off a primary crystal, but most often as single crystals. Sometimes the gypsum will form flower-like shapes or other shapes bound to sand. Or will contain inclusions of mud. Then there are the opaque types of gypsum such as the fibrous satin spar often incorrectly referred to as selenite. Just so much variety. Many stones have the same chemical make up but are not the same thing. For example chert, sugar quartz, chalcedony, jasper, agate, tridymite, coesite and cristobalite are just a few of the various forms of silicon dioxide. This does not mean they are all necessarily the same thing. I won’t get in to the fact that jasper and agate are forms of chalcedony yet can have differences from what it normally called chalcedony since that is not the topic. Point is that stones can have the same basic chemistry but have other differences such as crystal structure that make them different. In the case of gypsum all gypsum is hydrated calcium sulfate, but not all gypsum is selenite. In short if you want to know if your stone is really selenite simply hold it up to a light source. Can you see right through the gypsum like looking through glass? If yes then you have selenite. If no then you DO NOT have selenite. Selenite by definition is the CLEAR version of gypsum. So let’s look at the definition of some of the forms of gypsum: -Selenite: A clear version of gypsum that looks like glass and you can see right through it. Selenite may have inclusions in it, usually as inclusions of mud. Light still readily passes through the clear areas though. -Satin spar: A fibrous, translucent form of gypsum often used to make sculptures, towers, healing wands, palm stones, etc. If held up to the light you cannot see through it due to the fibrous nature. Very commonly mislabeled as selenite, which again is the clear version of gypsum. Alabaster: A form of massive gypsum for which there is no cleavage seen. May be opaque or can occur in clear crystals. Anhydrite: Technically no longer gypsum since anhydrite is calcium sulfate that is not hydrated. It can be produced by heating gypsum sufficiently to drive off the water. If water is added to anhydrite it converts back in to gypsum. Example of selenite: www.mindat.org/photo-138399.htmlExample of satin spar: www.mindat.org/photo-149274.htmlExample of alabaster gypsum: www.mindat.org/photo-213826.htmlExample of anhydrite: www.mindat.org/photo-288483.html |
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Post by fernwood on Aug 20, 2018 18:57:09 GMT -5
Thanks for the info. I was going on what the Rock Shed had labeled them as.
Appreciate your write up.
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Post by vegasjames on Aug 20, 2018 22:37:31 GMT -5
Here are examples of polished selenite crystals I did. Took the pic late it the day so color is not showing great. Some of the selenite is from red selenite crystals and the others from another deposit about a mile away that has a light gold hue.  20180820_174624 by James Sloane, on Flickr This is a red selenite crystal I polished and a friend wire wrapped:  20180820_174915 by James Sloane, on Flickr  20180820_175024 by James Sloane, on Flickr |
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pizzano
Cave Dweller 
Member since February 2018
Posts: 1,390
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Post by pizzano on Aug 21, 2018 0:32:43 GMT -5
Here is my write up I did on the different forms of gypsum. Clearing Up the Confusion About Forms of Gypsum. There seems to be a lot of confusion over the different forms of gypsum, which in particular is leading to the mislabeling of satin spar for selenite. So I figured I would write this to clear up the confusion. I really like gypsum because of its ability to form in so many shapes. I have collected crystals that look like angle wings, diamonds, one that looked like a bunch of little pentagons stacked on each other, some that look like fish skulls, blades, fish tails, swallow tails, hourglasses, crowns, etc., etc. etc. It also comes in different colors. I have been mining red selenite for years and have also found a deposit of golden selenite, and found one piece of green selenite and an interesting piece of gypsum that was root beer colored. Close by here is a humongous deposit of brown gypsum, some of which is as selenite. And occasionally I can find the clear “white” gypsum commonly referred to as “Utah glass”. Sometimes I find the selenite in clusters or as crystals growing off a primary crystal, but most often as single crystals. Sometimes the gypsum will form flower-like shapes or other shapes bound to sand. Or will contain inclusions of mud. Then there are the opaque types of gypsum such as the fibrous satin spar often incorrectly referred to as selenite. Just so much variety. Many stones have the same chemical make up but are not the same thing. For example chert, sugar quartz, chalcedony, jasper, agate, tridymite, coesite and cristobalite are just a few of the various forms of silicon dioxide. This does not mean they are all necessarily the same thing. I won’t get in to the fact that jasper and agate are forms of chalcedony yet can have differences from what it normally called chalcedony since that is not the topic. Point is that stones can have the same basic chemistry but have other differences such as crystal structure that make them different. In the case of gypsum all gypsum is hydrated calcium sulfate, but not all gypsum is selenite. In short if you want to know if your stone is really selenite simply hold it up to a light source. Can you see right through the gypsum like looking through glass? If yes then you have selenite. If no then you DO NOT have selenite. Selenite by definition is the CLEAR version of gypsum. So let’s look at the definition of some of the forms of gypsum: -Selenite: A clear version of gypsum that looks like glass and you can see right through it. Selenite may have inclusions in it, usually as inclusions of mud. Light still readily passes through the clear areas though. -Satin spar: A fibrous, translucent form of gypsum often used to make sculptures, towers, healing wands, palm stones, etc. If held up to the light you cannot see through it due to the fibrous nature. Very commonly mislabeled as selenite, which again is the clear version of gypsum. Alabaster: A form of massive gypsum for which there is no cleavage seen. May be opaque or can occur in clear crystals. Anhydrite: Technically no longer gypsum since anhydrite is calcium sulfate that is not hydrated. It can be produced by heating gypsum sufficiently to drive off the water. If water is added to anhydrite it converts back in to gypsum. Example of selenite: www.mindat.org/photo-138399.htmlExample of satin spar: www.mindat.org/photo-149274.htmlExample of alabaster gypsum: www.mindat.org/photo-213826.htmlExample of anhydrite: www.mindat.org/photo-288483.htmlSo, if I understand this correctly......Gypsum is not really considered a Chalcedony, therefore by definition, cannot also be an Agate or Jasper.....? |
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Post by vegasjames on Aug 21, 2018 1:09:39 GMT -5
Here is my write up I did on the different forms of gypsum. Clearing Up the Confusion About Forms of Gypsum. There seems to be a lot of confusion over the different forms of gypsum, which in particular is leading to the mislabeling of satin spar for selenite. So I figured I would write this to clear up the confusion. I really like gypsum because of its ability to form in so many shapes. I have collected crystals that look like angle wings, diamonds, one that looked like a bunch of little pentagons stacked on each other, some that look like fish skulls, blades, fish tails, swallow tails, hourglasses, crowns, etc., etc. etc. It also comes in different colors. I have been mining red selenite for years and have also found a deposit of golden selenite, and found one piece of green selenite and an interesting piece of gypsum that was root beer colored. Close by here is a humongous deposit of brown gypsum, some of which is as selenite. And occasionally I can find the clear “white” gypsum commonly referred to as “Utah glass”. Sometimes I find the selenite in clusters or as crystals growing off a primary crystal, but most often as single crystals. Sometimes the gypsum will form flower-like shapes or other shapes bound to sand. Or will contain inclusions of mud. Then there are the opaque types of gypsum such as the fibrous satin spar often incorrectly referred to as selenite. Just so much variety. Many stones have the same chemical make up but are not the same thing. For example chert, sugar quartz, chalcedony, jasper, agate, tridymite, coesite and cristobalite are just a few of the various forms of silicon dioxide. This does not mean they are all necessarily the same thing. I won’t get in to the fact that jasper and agate are forms of chalcedony yet can have differences from what it normally called chalcedony since that is not the topic. Point is that stones can have the same basic chemistry but have other differences such as crystal structure that make them different. In the case of gypsum all gypsum is hydrated calcium sulfate, but not all gypsum is selenite. In short if you want to know if your stone is really selenite simply hold it up to a light source. Can you see right through the gypsum like looking through glass? If yes then you have selenite. If no then you DO NOT have selenite. Selenite by definition is the CLEAR version of gypsum. So let’s look at the definition of some of the forms of gypsum: -Selenite: A clear version of gypsum that looks like glass and you can see right through it. Selenite may have inclusions in it, usually as inclusions of mud. Light still readily passes through the clear areas though. -Satin spar: A fibrous, translucent form of gypsum often used to make sculptures, towers, healing wands, palm stones, etc. If held up to the light you cannot see through it due to the fibrous nature. Very commonly mislabeled as selenite, which again is the clear version of gypsum. Alabaster: A form of massive gypsum for which there is no cleavage seen. May be opaque or can occur in clear crystals. Anhydrite: Technically no longer gypsum since anhydrite is calcium sulfate that is not hydrated. It can be produced by heating gypsum sufficiently to drive off the water. If water is added to anhydrite it converts back in to gypsum. Example of selenite: www.mindat.org/photo-138399.htmlExample of satin spar: www.mindat.org/photo-149274.htmlExample of alabaster gypsum: www.mindat.org/photo-213826.htmlExample of anhydrite: www.mindat.org/photo-288483.htmlSo, if I understand this correctly......Gypsum is not really considered a Chalcedony, therefore by definition, cannot also be an Agate or Jasper.....? No. Gypsum is a calcium sulfate and only has hardness around 2. Agate and jaspers are forms of chalcedony, which is a silicon dioxide related to quartz but with a different crystal structure. It is much harder than gypsum. |
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pizzano
Cave Dweller
Member since February 2018
Posts: 1,390
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Post by pizzano on Aug 21, 2018 1:28:14 GMT -5
Thanks....I got it.....Gypsum is not an Agate or Jasper or Chalcedony.......even though translucent or opaque, to soft and lack of silicon type crystal structures.....obviously not a tumbling material.........great write-up James.
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