# hbm:coltan_deposit

Places ore veins in narrowing bands around a seed-derived centre.

## Fields

| Field | Meaning and default | Range |
| - | - | - |
| `base_range` | Placement reach for the first band; later bands divide it by their index. | `i32` |
| `min_y` | Lowest sampled Y. | `i32` |
| `outer_attempts` | Number of outer placement attempts per chunk; use a positive value to place veins. | `i32` |
| `rings` | Number of narrowing placement bands per attempt; use a positive value. | `i32` |
| `spread` | Scale of the seed-derived deposit centre. | finite `f64` |
| `vein` | Vanilla ore configuration placed by an accepted attempt. | |
| `vein.size` | Maximum vein size. | `[0, 64]` |
| `vein.discard_chance_on_air_exposure` | Chance to discard ore exposed to air. | `[0, 1]` |
| `vein.targets` | Replacement targets and states. | |
| `vein.targets[].target` | Vanilla rule test selecting replaceable blocks. | |
| `vein.targets[].state` | Block state placed in the vein. | |
| `y_range` | Height of the sampled Y interval. | `[1, i32::MAX]` |

The top-level `type` selects this feature; the remaining fields belong beside it.

## Example

Source path: `data/hbm/worldgen/feature/deposit_coltan.json`

```json
{
  "type": "hbm:coltan_deposit",
  "base_range": 750,
  "min_y": 15,
  "outer_attempts": 2,
  "rings": 5,
  "spread": 1500.0,
  "vein": {
    "discard_chance_on_air_exposure": 0.0,
    "size": 4,
    "targets": [
      {
        "state": "hbm:ore_coltan",
        "target": {
          "predicate_type": "minecraft:tag_match",
          "tag": "minecraft:stone_ore_replaceables"
        }
      }
    ]
  },
  "y_range": 25
}
```