🧮 How to Estimate the Weight of Granite/Pegmatite Boulders
Granite and pegmatite are dense — they both clock in around 165–175 lbs per cubic foot.
Here’s a quick way to ballpark the weight:
👉 Step 1: Estimate the Size
Treat the boulder like a rectangular block (even if it’s rounded). Measure:
- Length
- Width
- Height
(Use inches, then convert to feet: divide each by 12.)
👉 Step 2: Calculate Volume
Volume (in cubic feet) = Length × Width × Height
👉 Step 3: Multiply by Weight
Estimated Weight = Volume × 170 lbs
(You can adjust for density — 165 for granite, up to 180 for some dense pegmatites.)
🛠️ How to Move a Heavy Boulder (Without Wrecking Your Spine)
🪵 1. Rollers + Pry Bars (Egyptian Style)
- Use sturdy pipes (PVC or metal) under the rock.
- Pry up one side and slide the first roller under.
- Push and roll while moving the back roller to the front as you go.
- Works well on flat ground!
🛷 2. Skid or Sled
- Place the boulder on a sheet of plywood, heavy-duty tarp, or metal sled.
- Drag it over grass/dirt.
- You can use ratchet straps and a vehicle or lawn tractor (slowly and carefully!).
🧱 3. Leverage + Planks
- Pry the boulder onto a board ramp or a wheelbarrow with a strong frame (if it’s not too massive).
- Or use a rock dolly (two wheels and cradle, specifically for boulders).
🚜 4. Rent a Tool
For larger rocks (300+ lbs), you can rent:
- Landscape dollies or boulder carts
- A come-along winch if you’re working on a slope
- Or even a mini skid steer or dingo loader for really big boys — local rental centers usually carry these for ~half-day rates.
🧠 Pro Tips:
- Use shims or bricks to slowly raise one side of the boulder at a time.
- Gloves, steel-toe boots, and eye protection are your friends.
- Always push from low on the rock — never lift with your back.