Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

How to Register on LPF | Buy Site Supporter Role (remove some ads) | LPF Donations

(A) Mineral phosphorescence

Well, it's softer than quartz. I no longer have all my mineral text books and it has been far too long since I even gave this field much thought. Sorry. I wish I could be of more help.
 





steve001 said:
This is the mineral in question. Do you recognize it?
Click to expand...

Looks to me like Scapolite, although, hard to tell from just a photograph.
It could also be a form of massive fluorite with Calcite. Again, I am shooting from the hip here.


What color does it fluoresce? Red/pink?

Those short wave bulbs require a UV bandpass filter, not woods glass to prevent the most of the blue and green light from the Hg discharge to obscure the fluorescence.
 
Seoul_lasers said:
Looks to me like Scapolite, although, hard to tell from just a photograph.
It could also be a form of massive fluorite with Calcite. Again, I am shooting from the hip here.


What color does it fluoresce? Red/pink?

Those short wave bulbs require a UV bandpass filter, not woods glass to prevent the most of the blue and green light from the Hg discharge to obscure the fluorescence.
Click to expand...

Color is mentioned on the first post. Interestingly it also photoluminesces the same color under 523 nm light.
 
Last edited:
steve001 said:
That is precisely the color my rock luminesces. Maybe Baryte is what I've got because it's found where I live.
Click to expand...


I had already suspected because of the look of your sample-picture and hang here therefore again a picture of my pattern in bright.
Baryte has a relatively high density of 4.5 g / cm3 and is therefore easy to verify.
 

Attachments

  • baryt.jpg
    baryt.jpg
    218.5 KB · Views: 17
Interesting. Since the density is relatively high, it might not be too difficult to determine if this is indeed baryte. Also, a loop of a small sample in a flame may help reveal its chemical composition. I was thrown by the spelling. I used to call this barite. It is the main source of barium in ore.
 
Last edited:
Barite, being a major barium ore is quite dense. Back when I was into mineralogy we use spec. gravity as a measure of density. It is easily done as you let the ore displace an amount of water equal to its volume.
 
steve001 said:
Often I use my 405 nm laser to see if it induces phosphorescence. Many do such as gypsum, titanium dioxide all of which give off a pale white light for a short time after excitation. But yesterday I found a mineral of some type that glows orange briefly.
Click to expand...

I've been doing this for years, It's a handy tool to have when looking for fluorescent and phosphorescent minerals as well. Calcite is especially responsive and has a reddish/orange glow for almost a full second after the beam passes! I'm guessing this is due in part to the drastic change in energy/wavelength of the light to the opposite end of the visible spectrum?
 
Many calcite examples are not fluorescent. I have a large piece of Icelandic calcite that is birefringent, but does not fluoresce at all. I have noticed this among calcite crystals especially.
 
Discovered more items that luminesce. I have an old cement utility sink. The cement luminesces white light for a few seconds gradually fading during that time. The cement making up the basement wall does the same.
 
Last edited:
paul1598419 said:
Many calcite examples are not fluorescent. I have a large piece of Icelandic calcite that is birefringent, but does not fluoresce at all. I have noticed this among calcite crystals especially.
Click to expand...

I also have a piece of Icelandic calcite and indeed it does not fluoresce, the birefringence is really interesting though! I always show my students when I teach my optics class, you can actually get a similar effect by laminating multiple pieces of glass with different refractive indices :)
I also have other samples of calcite that don't fluoresce and some that are green/yellowish, but the orange/red ones are the only ones that seem to trail behind the beam for a second.
 
steve001 said:
Discovered more items that luminesce. I have an old cement utility sink. The cement luminesces white light for a few seconds gradually fading during that time. The cement making up the basement wall does the same.
Click to expand...

Thats really interesting, any idea what is in the cement that is causing he fluorescence? I'll have to try that in my house, I definitely haven't noticed it before!
 
ev23 said:
Thats really interesting, any idea what is in the cement that is causing he fluorescence? I'll have to try that in my house, I definitely haven't noticed it before!
Click to expand...

No I don't. I have a flourite crystal that luminesces orange. Some other minerals such as calcite belonging to someone I know luminesce light blue or an orangish pink. Some common things around the house I may have mentioned earlier are white paint and plaster. All of them give off a pale white after glow. To date I've not found any naturally occuring minerals while hiking that
*luminesce or fluoresce. Like to find some that do.

*Except the one that started this thread.
 
You must log in or register to reply here.


Back
Top