Searching for Petrified Wood Along the Kakogawa River
(Stone Hunting, Part 2)
桂化木を探しに加古川に行きました（石拾い 第2回）
Following my previous outing — when I went looking for petrified wood — I headed back to the Kakogawa River to try to collect some.
I searched the riverbed in Ono City. The weather was clear, the water level had not risen, and countless stones were spread across the gravel bar. Not knowing where to start, I began by looking at my feet for any stones with a wood-grain pattern.
However, even when I found a few likely candidates, I could not be certain they were actually petrified wood. They were large and heavy, so I put them back on the spot.
I found myself wishing there were a scientific method — something like using a black light to identify fluorite by its glow — as I kept searching.
小野市の河原で採集します。よく晴れて増水もなく、河原には大量の石があります。どこから始めたらよいのか、とりあえず足元から木目がある石を探します。
しかし、何個かそれらしきものを見つけても、これが桂化木だと確信できません。大きく重いので、その場にリリースしました。
「ブラックライトを当てて蛍光を放つ蛍石を見つける」ような、科学的な手法があればいいのになあと思いながら探索します。
Scattered across the gravel bar were fragments of quartz that had been split open with a hammer. Someone had apparently been hunting for rock crystals. This spot clearly sees frequent visitors looking for stones — which made me start to wonder whether any petrified wood had already been taken long ago.
河原には石英の塊がハンマーで割られた破片が散在しています。水晶を探しているのでしょうか。ここは石を探す人が頻繁に入っているようです。それなら桂化木もすでに拾われて、見つけるのは難しいかもなと思い始めました。
In the end I did not find a single piece of petrified wood, so I tried gold panning for a change of pace. I collected sand from a turbulent spot where bedrock was exposed at the river's edge and swirled it in a pan.
I tried twice, but with my aging eyesight I could not tell the difference between fine sand grains and gold flakes. Still, I had fulfilled my long-held wish to try panning just once — and that was enough. I quickly gave up on actually finding gold.
⚠ The current there is fast and the spot is dangerous. Do not approach alone.
とうとう一個も見つからず、気晴らしに砂金のパンニングを試してみました。河原に岩盤の出ている激流スポットで、砂を集めパンニングします。
2回やりましたが、老眼の私には細かい砂粒と砂金の見分けがつきません。「一度パンニングをやってみたい」という望みが叶い、それでよし。砂金のゲットはすぐ諦めました。
⚠ 流れが早く、危険なスポットです。一人で近づかないようにしましょう。
Incidentally, all the tools needed for panning were available at a 100-yen shop: a plastic saucer intended for flower pots served as the panning dish, along with a small shovel, a miniature rake, a dropper, and a sieve.
ちなみにパンニング用の道具はすべて100円ショップで揃えることができました。植木鉢用の受け皿をパンニング皿に、スコップ、小型の熊手、スポイト、ふるい網です。
After about two hours on the riverbed, my son and I called it a day and headed home. Back at the house, I washed the two pieces of stone my son had picked up and examined them through a loupe — and to my surprise, they looked unmistakably like petrified wood!
What joy! The stones show fine parallel lines and have dark, charred-looking sections.
If anyone knowledgeable could tell me whether these are truly petrified wood, I would be very grateful.
2時間ほど河原を探索し、同行してくれた息子と引き揚げました。帰宅して息子が拾った2片の石を洗い、ルーペで見てみると、なんと、「どう見ても桂化木」なのです。
これはうれしい！細かい平行線が入り、炭化したような黒い部分がある。
有識者の方、桂化木かどうかご教示くだされば幸いです。
Key vocabulary · 重要語彙
木が長い年月をかけて鉱物に置き換わり石化したもの（珪化木・桂化木）。
Ancient wood whose organic material has been replaced by minerals over millions of years, turning it to stone while preserving the original grain structure.
"I was looking for petrified wood along the riverbed." / 「河原で桂化木を探していました。」
砂金採り。川の砂を浅い皿（パン）に入れ、水で揺すって比重の重い砂金を選り分ける技法。
The process of swirling river sediment in a shallow pan to separate dense gold particles from lighter sand and gravel.
"I tried gold panning but couldn't tell the flakes from the sand." / 「パンニングをやってみましたが、砂粒と区別がつきませんでした。」
拡大鏡・ルーペ。宝石師や地質学者が鉱石・化石などを精密観察するために使う小型手持ち拡大鏡。
A small hand-held magnifying glass used by geologists, jewellers, and collectors to examine fine details in minerals, fossils, and gemstones. An essential field tool.
"Examining the stone through a loupe, I could see fine parallel lines." / 「ルーペで見ると、細かい平行線が確認できました。」
