No, they are quite common. For example, both sugar and salt come as crystals.
sandstone has crystals, big ones not small ones
Yes, they can "grow".
CRYSTALS
crystals
calcite
They are not rare nor are they hard to find .
Yes. Most gems are crystals, but the vast majority of crystals are not gems.
crystals
Halos around the Moon are not particularly rare, but are dependent on the formation of tiny ice crystals in the upper atmosphere.
Mouldy crystals. They are the most rare crystals in the world. First a bear has to vomit on it, then a fox has to poo on it and a dog has to wee on it then to finish this amazing glory a human being has to consume and poo out the remains. This how you get bright yellow crystals. :D
Rarity is relative. My experience and a quick perusal of mindat.org would suggest that jarosite is not very rare. (There are many hundreds of localities, and fine micro crystals can be easily purchased for a few bucks.) However, jarosite is indeed rare in large crystals or fine specimens of display quality.
Gemstones are more valuable and rare and have more vibrant colors and come in more colors. There is more types of gemstones then crystals.
Adelite is a rare mineral, forming blue, green, yellow or grey orthorhombic crystals.
An aerugite is a rare complex nickel arsenate mineral with green to blue-green trigonal crystals.
Surprisingly it does! I've actually researched a bit of this and came up with the answer that only females really do pee crystals but you might get a rare male that does too. Hope this helped :)
Me, again. The rare naturally curly kind. The ones that look like you curled them beautifully.
Just keep defeating them, youll eventually get one but they are very rare