Here are a few options for a WordPress post_tag description in Traditional Chinese for the title “蛋白石鑑定”, with varying levels of detail:

**Option 1 (Concise):**

> 蛋白石真偽辨識與評估。

* **Translation:** Opal authenticity identification and assessment.
* **Pros:** Straightforward, good for general searches.
* **Cons:** Lacks context, might be too generic.

**Option 2 (More Detail):**

> 蛋白石鑑定的各種方法，包括顏色、光澤、結構、火彩等方面的分析，幫助你判斷蛋白石的品質與價值。

* **Translation:** Various methods for opal identification, including analysis of color, luster, structure, fire (play-of-color), etc., to help you assess the quality and value of opals.
* **Pros:** More informative, provides a good summary of the topic.
* **Cons:** Might be slightly longer for some search result presentations.

**Option 3 (Focus on Practical Application):**

> 想知道如何鑑定你的蛋白石？瞭解蛋白石鑑定的關鍵要素，避免買到假貨，確保你的收藏物有所值。

* **Translation:** Want to know how to identify your opals? Understand the key elements of opal identification, avoid purchasing fakes, and ensure your collection is worthwhile.
* **Pros:** Appeals to a specific user need (avoiding fakes), more engaging language.
* **Cons:** Might not be as useful for all readers, less comprehensive.

**Option 4 (Academic/Expert-Oriented):**

> 蛋白石鑑定：寶石學角度的蛋白石特性分析，包括物理性質、化學成分與光學現象，並探討其市場價值。

* **Translation:** Opal Identification: An gemological analysis of opal characteristics, including physical properties, chemical composition, and optical phenomena, and explores its market value.
* **Pros:** Targets a knowledgeable audience.
* **Cons:** Too specific/technical for casual readers

**How to Choose:**

* **Target Audience:** Who are you trying to reach (experts, beginners, collectors)?
* **Content of the Post:** What does the post itself cover? The description should accurately reflect the post’s content.
* **SEO Considerations:** (Optional) Include relevant keywords (e.g. “顏色”, “光澤”, “真偽辨識”) to improve search visibility. Ensure the chosen keywords align with the detailed post context.

**Recommendations:**

I recommend either **Option 2** or **Option 3** depending on the tone and content of your actual blog post. Option 2 provides a well-rounded overview, and Option 3 is more actionable for readers.