Joined: Sun Oct 16, 2005 3:36 pm Posts: 192 Location: San Francisco
So, awhile back I promised I had some "stuff" to get rid of around here and I would post a few quizzes to give it away. Well, here's the first. This isn't so much a quiz as a picture identification. I'm posting links to 10 different crystals (or parts thereof) and the first person to correctly identify all 10 will be declared the winner.
Some of these will be easy and I will not be providing any additional information. For those that are more difficult to identify from a photo, I will include the occassional clue. 3-1 and 3-2 are the same gem, the photo is taken with light shining through the A and B axes.
So what's the prize? I'm starting the first quiz off with a book; an unused paperback copy of Emeralds by Fred Ward. It is the Revised Edition, Copyright 2001 and I will cover the shipping costs.
Joined: Sun Oct 16, 2005 3:36 pm Posts: 192 Location: San Francisco
gemma;
Sorry, I guess I didn't put any rules...
Post, don't PM, so everyone can see the guesses.
Guess as many or as few as you want with a post.
First person to post with all 10 gems correct (in a single post) gets the book.
I guess I'll include a clue for number 3 while I'm posting. I think in was gemca who described this gem in a post some time ago and that's a maglight behind the stone.
Joined: Sun Oct 16, 2005 3:36 pm Posts: 192 Location: San Francisco
gemca;
Not bad, 50% from a few pictures...
1. yes
2. no
3. no ( thought you would have guessed this one, it's the same as one of your posts )
4. no
5. no
6. no
7. yes
8. yes
9. yes (excellent guess)
10. yes (it does occur as octahedrons)
The prize is still available.
Here's a clue for number 4: Think high dispersion (I guess that applies for number 5 as well)
Joined: Sun Oct 16, 2005 3:36 pm Posts: 192 Location: San Francisco
Doos;
More good guesses, unfortunately they aren't all correct..
1. yes
2. no
3. no (look for other photos of cut stones on this board)
4. no (similar dispersion to your guess for 5 but different gem)
5. no (think much higher dispersion along with the initials MSH)
6. no
7. yes
8. yes
9. yes
10. yes
Joined: Sun Oct 16, 2005 3:36 pm Posts: 192 Location: San Francisco
gemca;
2. no
3. yes (that is a chrome kyanite, it changes color down one axis with incandescent light)
4. no (think higher dispersion and MUCH higher SG)
5. no (think MUCH, MUCH, MUCH higher dispersion)
6. no (this type is usually other pastel colors but occasionally you see one colored by Cadmium)
There, I think that should be enough information for someone to guess them all correctly
Joined: Mon Oct 17, 2005 2:52 pm Posts: 241 Location: France | French Riviera
I didn't know for the specific change of color along axis..
I had just noted a red (fluorescence) coloration.
Very very interesting!! I will check my Cr-Kyanite for this behavior
Other guess.
2. Enstatite (brown one from tanzania may be??)
4. ???? hum....Cubic zirconia??? I am very dubitative about my own guess beacause of the cristal habit.
5. Sphalerite (very rare in green..but I try....you have Proustite and Cr-Kyanite.. you can have a lot of other amazing stuff ) but the cristal dont look cubic ??
6. Fluorite (I don't know about Cadmium colored stone..this is a pure random guess)
Thank you ars for this very intructive quizz!
I will do a image quizz to
Joined: Sun Oct 16, 2005 3:36 pm Posts: 192 Location: San Francisco
gemca;
I found the color change in the kyanite by accident. I knew it contained chromium and since many other chromium containing stones behave differently with different light sources, I subjected it to all kinds of light in all kinds of situations. Lo' and behold, there was the color change.
Know to your latest guesses...
2. no (this gem is triclinic and strongly trichroic and you could say it is "bladed")
4. no (not cz however, the sg is very high, higher than cz. One word: Tsumeb)
5. yes (it is a sphalerite, it's a bad photo from a bad angle)
6. no (see previous clues on pastel colors and cadmium)
Well, there you go folks. With all the previous clues and correct guesses, someone should be able to put a post together with all 10 gems correct.
Users browsing this forum: No registered users and 16 guests
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum