Thursday, September 5, 2019


A rock that insists on telling you a story is a great rock to get to know! This Sagenite Rutile is an amazing storyteller. I see a wheel in motion over a coarse surface. What do you see?
Credit: Marco Campos-Venuti Collection

According to this site Sagenite can come in geometric patterns  This variety is formed when a pattern of crossed Rutile crystals is present with angles of 60 degrees that is the twinning law of Rutile. 
Credit: Marco Campos-Venuti Collection
Sagenite loves to tell stories. At least the kind I work with in my lapidary shop does. There are apparently two schools of thought when this name is used to describe a rock. There's the one that describes stones with vibrant, puffy strands that appear to be moving with an unseen tide. I absolutely love these. The other is a variety of rutile  where the crystals criss-cross  in a geometric sort of pattern. The look is so distinctive that back in 1796, it was named sagenite  from the Greek and Latin word "sagena" or net. This piece looks positively architectural to me.


I haven't been able to acquire any saginite rutile to work on, but I've had a lot of fun with the kind that makes soft swirls.

 I fell in love with the slab I used to create this cabochon!  It has the yellowish Sagenite, along with white tube structures you can just see inside the clear agate, and a vug that comes across as a whirlpool that is causing the Sagenite to swirl around.
Pat McMahan, renowned agate expert, wrote that these Sagenetic filaments are often arranged in fans or sunbursts in the agates and can come in different colors. That is because the Sagenite in Agates is a pseudomorph (where one mineral replaces a different one that has already created the shape). As an interesting aside, he feels that the Sagenetic structures form in the still-hardening agate and they don't extend into nearby banded agate which is formed at a different time.

This cool piece of Sagentic agate really shows off the way the filaments can arrange themselves in groups of fans.

The way it has a central open space in the agate with the filaments swishing around it, makes me think of that sight you see when you're in your car as it goes through the automatic car wash. All those soft things rotating and slapping your car as you go through.

The vendor who sold me this had a lot of slabs of this material. I asked him what it was and he wrote "Sagenite" on the slab I purchased.

I've had other people who have seen it agree that it is Sagenite, but it's different from my other pieces because there's no cluster that the formations spring from.

However, I love the look like it's from a pot of spaghetti and it polishes like a dream!

 Do you have a favorite agate cabochon that features sagenite?  I'd love to see a picture of it!

ROCK SHOW SEASON IS JUST AROUND THE CORNER. I'd love to hear from you about what makes your show (or your favorite show) special. Don't forget pix!  Send to

Until next time, have fun with your rocks!

Your Lapidary Whisperer


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