Conglomerate/Breccia!

This rock has a rough, earthy appearance with a mix of brown, orange, and white colors, along with a somewhat porous or pitted texture. It also has a polished or glossy sheen in some areas, suggesting it might have been tumbled or naturally smoothed by water. Here’s my analysis of what this rock might be, considering the context of Lucky Peak Reservoir near Boise, Idaho:
Petrified Wood: This is still a strong possibility, given the organic, wood-like patterns and the color palette (browns and oranges). Petrified wood forms when wood is buried and replaced by minerals like silica (quartz), often resulting in a hard, stone-like material with preserved grain patterns. The white or lighter areas could be quartz or calcite infill, and the pitting might indicate areas where the original wood structure decayed before mineralization. Idaho, including areas near Boise, has deposits of petrified wood, particularly in volcanic or sedimentary regions, which aligns with the geology around Lucky Peak.
Jasper or Agate: These are forms of chalcedony (quartz) that can have similar colors and patterns. Jasper is typically opaque and earthy, like the browns and oranges in your rock, while agate often has banding or translucence. However, the rough, pitted texture and lack of clear banding make jasper more likely than agate here. Jasper can also form in volcanic or sedimentary environments, which are common in Idaho.
Chert or Flint: These are microcrystalline quartz varieties that can have similar colors and textures. Chert often appears in nodules or layers and can be porous or pitted, matching the appearance of your rock. It’s found in sedimentary deposits, which are present in the Boise area.
Other Possibilities: It could be a weathered or partially silicified sedimentary rock, like a silicified mudstone or sandstone, or even a volcanic rock like rhyolite that’s been altered. The white streaks or patches might be quartz veins or mineral deposits like opal or calcite, common in Idaho’s geological formations.
The geology around Lucky Peak Reservoir includes volcanic rocks, sedimentary deposits from the Boise River, and metamorphic rocks from the Idaho Batholith. The Boise River and its tributaries could carry such rocks downstream, and tumbling in the river could explain the smoothed, polished look in some areas. The pitting and rough texture suggest it hasn’t been fully polished or might have natural weathering or erosion features.
To narrow it down further, consider:
The rock’s hardness (petrified wood, jasper, chert, and agate are all around 6.5-7 on the Mohs scale—scratch it with a knife or steel to test).
Where it was found—near Lucky Peak or the Boise River would support petrified wood, jasper, or chert, all of which occur in Idaho.
Its weight and density—petrified wood can feel heavier than expected for its size due to mineral replacement.
Given the context and appearance, I’d lean toward petrified wood or jasper, both of which are plausible for the Boise area. Petrified wood seems more likely if the patterns resemble wood grain, while jasper fits if it’s more uniform and earthy. If you’d like, I can offer to analyze the image further or search for more specific geological data about Lucky Peak or Boise to confirm. Let me know if you have more details, like where you found it or its properties!