As of my last update in January 2022, I don't have specific information about Sierra Jewels Co or their inventory. However, if you're looking for men's diamond jewelry, it's essential to consider a few factors:

1. **Quality**: Ensure that the diamonds are of high quality, with appropriate certification if possible. Look for clarity, color, cut, and carat weight.

2. **Style**: Consider the style preferences of the person who will be wearing the jewelry. Do they prefer something classic, modern, or more unique?

3. **Budget**: Diamonds can vary widely in price depending on their quality and size. Set a budget beforehand to narrow down your options.

4. **Materials**: Besides diamonds, consider the metal used in the jewelry. Common choices include gold (white, yellow, or rose), platinum, or silver.

5. **Retailer Reputation**: If you're buying from Sierra Jewels Co or any other retailer, check their reputation, return policy, and customer reviews to ensure a satisfactory purchasing experience.

6. **Customization**: Some jewelers offer customization options, allowing you to create a unique piece tailored to your preferences.

If Sierra Jewels Co offers men's diamond jewelry, you can explore their collection while considering these factors. Alternatively, you can also explore other reputable jewelers both online and in-person to find the perfect piece.

As of my last update in January 2022, I don't have specific information about Sierra Jewels Co and its inventory. However, if Sierra Jewels Co offers men's diamond jewelry, it likely includes a range of items such as diamond rings, bracelets, necklaces, and earrings designed specifically for men. These pieces may feature diamonds as the main gemstone or as accents, and they could be crafted from materials like gold, platinum, or sterling silver. To get the most accurate and up-to-date information about Sierra Jewels Co's offerings, I recommend visiting their website or contacting them directly.