Mineral Mondays #8: Agate, Plus Win These Agates!
Agate
Agate is a cryptocrystalline of silica. It's a variety of chalcedony, pronounced Kal-sid-ni, and is considered by some as a semi-precious gemstone. They are formed in cracks and pockets in rock, usually volcanic, when tiny fibers made of quartz crystals build up layer upon layer over long periods of time. Agates have been used all over the world throughout histrory because it's common, comes in amazing patterns and takes a high polish. I'm giving these two agates away to a US resident. Read on to find out how to win them! .
Agates are one of the entry stones into gem & mineral collecting because their patterns and colors are so eye catching. In addition to that they can be collected fairly easily across the world if you know where to look. In California the Mojave Desert is littered with them. Due to government restrictions and decades of collecting finding the amazing specimens takes work, but they are still out there.
One of my favorite agates comes from Clear Creek, California and is known as plasma agate. It's a combination of agate, jasper and cinnabar and produces some incredible patterns when polished. They are prized by cutters for use in knife handles and as cabochons. Jay Fisher is one such famous cutter and you can view some of his beautiful creations here: http://www.jayfisher.com/Handles_Knife_Gemstone1.htm
Some facts about agate:
- Agate is a cryptocrystalline mineral
- Shape - varies, depends on void they fill
- Composition - silicon dioxide
- Hardness - 6.5 - 7 (upper medium, diamond is 10)
- Refractive index (fire) - 1.53 - 1.54 (diamond is 2.417 - 2.419)
- Colors - Red, Gray, Blue, Green, White, Yellow & Brown
- Localities - All over the world, too many to list
Lastly, when I was hunting for jadeite and benitoite in Itoigawa, Japan last year I came across this Menou 瑪瑙, agate in japanese. I wasn't looking for agate, but now that I know it's found on the beach there I'll be keeping my eyes open next time I visit.
Ok, contest time. Guess the total weight of the two agates pictured in the first photo on this post and leave your answer in the comment section. Only one guess per person. The first person to guess correctly will one. If no one guesses correctly then the closest answer by Sunday evening PST will win. Sorry, not hints either! Good luck!
Only open to US residents, unless you are willing to pay for overseas shipping.
Congratulations to @shasta for winning last week's mineral, turquoise!
Next week's Mineral Mondays #9: Quartz
Thanks for reading!
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Beautiful stones! Upvote and Resteem
Thank you. Are you in the States? If so, guess the weight and the first two could be yours.
Yes, I am in Hawaii
Beautiful stones, i mean minerals... nice rocky things you've got there !! (-:
4.56 oz. I like the look of that beach in Japan I guess. We have a very similar looking beach with a lot of agates we go to for our hunts. A couple of weeks ago I found 3 marble sized and shaped agates, two clears, one yellow. I posted a picture of one of the clear ones, about 2 weeks ago, and a small yellow saucer shaped one I found about 4 days ago. We do not get real big beach agates, but they certainly are brilliant.
Will let you know on Sunday if you are the winner.
That beach is amazing. Miles of tumbled stones, jadeite, mariposite, chromite, nephrite, agate, etc. The geology is very similar to California's Diablo Mountain range so it produces many of the same minerals.
I have no clue what " jadeite, mariposite, chromite, nephrite" are, but my wife most likely does, The agates are not hard to figure out, they shine and sparkle, so catch the eye.
Agates are my most favorite to hunt for on the beaches when the
sun angle is just right they pop out like diamonds as you walk along.
Those Jay Fisher knives are out of this world gorgeous!
I'm so excited I won last weeks beautiful mineral turquoise!
Is it ok to enter this contest each week if I already won once?
Thank you @rt395 for all the mineral knowledge and awesome pictures!