Opal
Opal is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. The name opal is believed to be derived from the Sanskrit word upala (उपल), which means 'jewel', and later the Greek derivative opállios (ὀπάλλιος), which means 'to see a change in color'. There are two broad classes of opal: precious and common. Precious opal displays play-of-color (iridescence); common opal does not.5 Play-of-color is defined as "a pseudo chromatic optical effect resulting in flashes of colored light from certain minerals, as they are turned in white light."6 The internal structure of precious opal causes it to diffract light, resulting in play-of-color. Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque, and the background color may be white, black, or nearly any color of the visual spectrum. Black opal is considered the rarest, while white, gray, and green opals are the most common.
The Urban Dictionary Mug
👍

The mug exceeded my expectations. Really excellent quality and build
Jim, you’re a fucking idiot interfering with accurate ratings and legitimate feedback. Get a hobby.
Great gift!
A little spendy, but worth it.
My wife kept talking about "ways out" being a Denver version of "psych" and she was right, so I got her this once I found it on UD. She loved it!
It's a great mug, will reccomend to family members my grandma gave me this mug for christmas and it was by far the best gift i got.
It arrived three weeks after ordering but given the holiday rush and inability of shipping to keep on schedule arrived late but was perfect little gift from me to my wife for her morning coffee with her "nickname" on the mug.
I liked the photo on your website and so I ordered the mug. You sent it right away, and it looks great!
Arrived carefully packaged

me and the boys when i get vodka mug
I ordered 3 of your mugs, with different names on them. There was a typo in the information about the name on the back of each of the mugs. This wasn’t a dealbreaker because the people who received them liked them. However, it would be nice if somebody who has basic proficiency in spelling English words could proofread the script for all of your names before they’re prepared.
Arrived on time. Great packaging. Communication with vendor was top-notch. High quality item.

I love it! Thanks! So
Great present for a retiring colleague with custom saying she's known for!

Loved this mug! So unique and you can edit the text to add something unique.
I gave it to my friend who took money from me and never returned.
I love the fact that I was able to customize my name since I've never been able to find anything with my name. The only downside is it's smaller than I thought it would be (I guess I didn't pay much attention to that), wish it was bigger, only about 10 oz total.
It's simply awesome; and plus, the word means a lot.
Really fast and looks great! Took a chance on Christmas gift and it was a success!
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