One of the awesome things about the universe is that it's big enough for crazy-wonderful things to happen. Luckily, astronomy lets us see them. For example, there's a star where it's raining olivine crystals right now.
Far away, in the constellation of Orion, a young proto-star called HOPS-68, is forming. Stars form by attracting mass with their gravity, and pulling it in. As more and more matter builds up on the surface of the star, the star condenses and the center starts to be crushed. Putting a force on matter heats it up, and so the center of the star heats. When it eventually heats enough to cause nuclear fusion, the proto-star joins the big leagues. In the meantime, hot material expands outwards, becoming less dense and so rising up through the material of the star. Some highly-heated material, in liquid form, escape to the surface of the star, like magma or lava leaking from the volcanoes on earth.
On HOPS-68, the escaping hot liquid caused the material olivine to be formed, then liquified, then shot on a jet of gas up into the atmosphere. There, among clouds of material, the material cooled until it was tiny crystalline specs of a particular type of olivine called forsterite, and rained back down towards the surface or swirl in the clouds.
Scientists say that, on the forming star, the clouds around the forming star will cut out most of the light, but what light that gets through will shine off the tiny crystals. Someone in the clouds - wearing the proper safety gear of course - would see a dark background of swirling material, dotted with tiny, temporary specs of brilliant green as a young star forms underneath them.
Sometimes science looks like it's trying too hard to be poetic.
Crystal rain: Shutterstock
Gem: Rob Lavinsky, iRocks.com