Japanese Hardness Testing Kit

Mineral Matters #433

Less than eight weeks until our Japan trip!

A number of years ago, I found a vintage Japanese hardness testing kit. This was before I took more of an interest in Japanese minerals.

It is an interesting, and useful, set. It contains samples for each hardness from talc to corundum. There isn't a diamond for 10, but there is a rod with the remains of a diamond embedded in the tip. There is also a streak plate. The wooden box is 250mm wide.

Here is what is written on the outside of the lid as far as I can determine:

In the top left corner, handwritten (circled in red in the closeup image) may relate to:

• 昭和 42 - Year 42 of the Shōwa era, which corresponds to the year 1967 in the Gregorian calendar. Note that the handwritten kanji are not that clear, so this is a best guess.

Central Label:

• English: Mohs scale of Hardness

• Japanese: モース硬度計 (Mohs Hardness Scale)

Left Side:

• 品日 (Item) | モース硬度 (Mohs Hardness)

• 番号 (Number) | H.K. 3.3

• 取得日 (Acquisition Date) | 3 42 (March 42nd year of the Shōwa era, which is 1967) - this tallies with the handwritten kanji.

• 摘要 (Summary) | 理 (Reason or Arrangement?)

Bottom Centre:

• Kent (probably the manufacturer)

• 内田洋行 科学器部 (Uchida Yoko Science Equipment Department)

• 東京·大阪·桃城·品研 (Tokyo, Osaka, Momojō, Shinken)

Here is the text from the inside of the lid:

モース硬度計 (Mohs Hardness Scale)

1. 滑石 Talc

2. 石膏 Gypsum

3. 方解石 Calcite

4. 螢石 Fluorite

5. 磷灰石 Apatite

6. 長石 Orthoclase

7. 石英 Quartz

8. 黄玉 Topaz

9. 鋼玉 Corundum

10. 金剛石 Diamond - (ダイヤモンドガラス切) “Diamond Glass Cutter”

Below: Contents of hardness kit.

Below: Outside of lid:

Below: Closeup of top left corner of lid:

Below: Inside lid: