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Dendrite Butte, Oregon: Rockounding Guide

dendrite butte rockhounding oregon

Rockhounding Dendrite Butte, Oregon

Dendrite Butte is another prominent Central Oregon rockhounding destination, situated 55 miles east of Prineville and near the Congleton Hollow Rockhounding Site.

Dendrite Butte is considered a Limb Cast Collection Area. The site is well-known for limb casts in blue, pink, and green hues. Opalized and petrified wood may also be found at the Dendrite Butte location.

Surface hunting for specimens at Dendrite Butte is becoming more and more difficult. That’s because the area has been a popular destination for rockhounds over the years.

With that said, there are still many more specimens to be found. You just have to be willing to do some digging.

Besides digging your own hole to start looking, I recommend following in the footsteps of folks who have already been in the area. Look for areas where they’ve already started digging. These older dig sites can be excellent clues in finding your own petrified wood.

About Dendrite Butte

The BLM has classified the 540-acre Dendrite Butte as a recreational rock and mineral gathering site, and it is mentioned on the Central Oregon Rockhounding Map, which is available for purchase.

When driving to the gathering location, material may be acquired on the northern side of the road or on the left. On the right, the road is a border of the South Fork Wilderness Study Area. On wilderness property, digging is not permitted.

When it rains, the road becomes rough, uneven, and muddy. Four-Wheel Drive is advised.

More Useful Information for Visiting Dendrite Butte

Open: Best time: May-October
Managed: BLM

What You Can Find: Limb casts, petrified wood, opalized wood

Activities: Rockhounding, camping, and wildlife observin

Accommodations: Camping is permitted on BLM land

Road access: 4WD vehicle is recommended, the road can become very muddy and inaccessible during wet weather.

Fees: None

Elevation: 4,450 ft (1,356 m)

Distance From Major Cities:

  • 55 miles southeast of Prineville
  • 80 miles east of Bend
  • 204 miles southeast of Salem.

How Limb Casts Are Made

When agate, chalcedony and other minerals are deposited in cavities made by tree branches coated in volcanic ash, it forms limb casts. After being blanketed by hot ash, the wood burns away. As a consequence, a chunk of agate in the shape of a tree limb is formed, thus the term limb Cast. The bark and wood textures are visible in some of these castings making them look like branches, or dendritic.

Different Types of Petrified Wood

There is no strict classification of petrified wood. In the past there were some attempts to make a classification based on the type of plant. Unfortunately, not all the samples of petrified wood hold the features of the initial plant.

Petrified wood can be subdivided according to its color described above.

The mineral composition of petrified wood can make up the base for the second classification. Petrified wood can be composed of:

  • Quartz – the most abundant mineral at Earth’s surface composed of  SiO2 . 
  • Chalcedony – a cryptocrystalline variety of quartz. Cryptocrystalline means no crystal grains are possible to observe with the naked eye.
  • Agate – a variety of chalcedony, but unlike chalcedony, it displays layered texture.
  • Opal – a mineraloid. It has the same chemical composition as quartz, but a different crystal structure. Opal displays the opalescence effect that could be described as color flashes inside the stone.

Facts About Petrified Wood!

  1. The first and most crucial point to remember is that petrified wood cannot be used as firewood! Petrified wood, no matter how it seems, is no longer a tree. It is, in reality, a stone, despite its look!
  2. Giant pieces of petrified wood may be discovered (up to several meters). It’s really rather charming to read of landowners who pull out whole tree trunks, or even complete petrified trees! Petrified wood, like regular wood, may be utilized for furniture or interior construction in this situation. Of course, the tabletop will be much heavier and more costly.
  3. Petrified wood is very tough. The composition of silica explains its hardness. It is rated between 7 and 8 on the Mohs Hardness Scale due to quartz, which is the major ingredient of petrified wood, which is rated 7 on the same scale. On the Mohs hardness scale, talc is a 1 and diamond (the hardest natural substance) is a 10.
  4. Petrified wood is not as rare as sapphire or diamond. It is found all throughout the globe, however the grade of the material varies from region to location.

Where Is Dendrite Butte?

Dendrite Butte is located near Congleton Hollow. See map below.

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