Syenite

Synne Syenite, 275 million years old. Syenites are igneous rocks and differ from granites in that they contain much less quartz, or are completely without quartz.

Maybe you can see the family resemblance? Many people think I look like my cousin, Geir Granite! We are from the same family, and we all come from molten rock. So once, a long time ago, I was a kind of hot porridge deep down in the Earth's crust. When molten rock cools down-maybe because it moves upward into cooler parts of the crust-it will eventually solidify into a rock. And that's how I was formed.

Not all magmas are the same; they can contain many different ingredients. Just like when you bake: to make chocolate cake, you need to add chocolate. But you don't add chocolate if you're baking whole grain bread! Or you don't put finely chopped onions in cream if you're making ice cream! There can be many different rocks formed from molten rock, or magma, as geologists call it. I don't sparkle as much as cousin Geir, because syenites don't have as many shiny quartz crystals as he does! Some syenites have no quartz at all, and that's exactly how I am! But I have something not everyone else has-a more unusual mineral called nepheline. I'm proud of that! In Oslo, you can find many of my relatives, with fine names like grefsensyenite and nordmarkite.

Facts

Syenites are igneous rocks and differ from granites in that they contain much less quartz, or are completely without quartz82. Syenites and granites crystallize slowly, so they appear rather coarse-grained. In the Langesundsfjord, at the western edge of the Oslo region, there is a special syenite called nepheline syenite.

Nepheline and quartz do not occur together. Many of the pegmatite veins here can also be nepheline syenitic. When mineralogists are looking for new or special minerals, it is the pegmatite veins they check!