Helzberg Diamonds, located at 244 Sun Valley Mall Space D116, Concord, CA 94520, is well-regarded for its engagement ring creation and exceptional customer service. The store operates in Contra Costa County and boasts a selection of high-quality diamond jewelry suitable for various occasions, including customizable engagement rings. Customers appreciate the knowledgeable staff's guidance throughout the process of selecting or designing the perfect ring, often highlighting their patience and expertise.

Operating hours are as follows:

| Day | Hours |
|-----------|---------------------|
| Monday | 11:00 AM - 7:00 PM |
| Tuesday | 11:00 AM - 7:00 PM |
| Wednesday | 11:00 AM - 7:00 PM |
| Thursday | 11:00 AM - 7:00 PM |
| Friday | 11:00 AM - 7:00 PM |
| Saturday | 11:00 AM - 7:00 PM |
| Sunday | 12:00 PM - 6:00 PM |

Overall Sentiment from Online Customer Reviews:
The store enjoys a generally positive sentiment from online reviews, with approximately 85% classified as positive. Customers frequently commend the helpfulness and friendliness of the staff, though some reviews reflect concerns regarding service consistency and warranty issues.

Best Review:
A customer named Jaime appreciated the outstanding assistance provided during their engagement ring shopping experience, praising the staff's attentiveness and their effective communication throughout the custom order process, leading to an exceptional final product.

Worst Review:
A review from A T expressed frustration with the store's service, reporting dissatisfaction with a ring repair that led to a missing diamond. The reviewer noted a lack of accountability when raising concerns about the workmanship.

* For this overview, customer feedbacks were viewed on Yelp, Google, and Facebook.