No two alike? Not any more....



This page describes some "identical-twin" snowflakes I have been making in the lab. I use this term because, like identical-twin people, these snow crystal twins are clearly very similar to one another, although they are not precisely identical.

This image shows a pair of designer snowflakes that grew near one another. Because the two crystals experienced the same changing growth conditions, they grew into nearly the same shape.



These are real snow crystals -- slivers of ice that materialized from water vapor in the air. In this photo they are surrounded by a field of tiny fog droplets. You can read more about how all this works on the designer snowflakes page.





This movie shows the growth of a pair of identical-twin snowflakes.

High-resolution version

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Last frame



This is not a computer simulation, nor it is PhotoShop trickering. These are two genuine, separate snow crystals, that I arranged to grown side-by-side in the lab.



It took 16 minutes to grow these crystals, so the movie plays about 60 times faster than real life. At the end of their growth, each crystal measured 2.0 millimeters (0.08 inches) from tip to tip -- a bit larger than the head of a pin.





This movie shows the same pair of crystals, but displayed side-by-side to make it easier to compare their features.

High-resolution version

Medium resolution

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Last frame



What made it possible to grow identical-twin snowflakes was the ability to grow designer snowflakes under carefully controlled conditions. I put a lot of time and effort into building my apparatus with sufficient temperature control, humidity control, positioning control, and air flow control. Once I was able to create and photograph growing snow crystals in the lab in a well regulated environment, I was also able to grow identical-twin snowflakes.





Here are two additional examples of growing identical-twin snowflakes (in high-resolution):



low-resolution :: mediurm :: high

low-resolution :: mediurm :: high

Snow crystal symmetry requires symmetrical growth conditions. If the six arms experience different environments, they will grow differently.



Consider this pair of identical-twin snowflakes. At this stage in their growth, each crystal developed independently of the other. But as they grew larger, the branches of one crystal began interfering with the branches of the other.

Here are the same two crystals after some additional growth. The outer branches grew nearly identically on both crystals, but the inner branches had no room to grow, so they became stunted. As the arms grew closer together, they competed for the available water vapor.