




Mare Nubium Gray Spinel engagement ring
18k gold and gray spinel
Long ago it was believed that there were beautiful seas and lakes of water on the moon that were visible from Earth. Galileo looked through his telescope and named them all. This ring is named after one of those lakes, the Mare Nubuim.
A bold and classic style with an ancient silhouette, created here with gorgeous gray spinel and black diamonds, and cast in solid 18k recycled yellow gold.
The subtle flare and sculpted style on the ring shank refers to an old European style of ring that is comfortable to wear.
Let us guide you
Work with Kelly to guide you through the process of ring selection.
Contact her below to answer any questions and begin curating your ring suite.

Join forces with Kelly, our head designer, to design this extraordinary ring!
She will expertly navigate you through the various setting options that cater to your lifestyle, as well as provide valuable insights on selecting the perfect diamond.
Contact us here to book a complementary virtual appointment!
Our Midheaven Collection engagement rings are Bespoke, custom made to order for you in your exact ring size and set with a select lab grown or natural diamond of your choosing. GIA Diamond Certifications and fine jewelry evaluation reports are sent digitally with your finished piece.
Available ring sizes are whole, half and quarter US sizes ranging between size 3 to size 12.
Our Concierge will contact you to confirm your true sizing after purchase. Feel free to Contact us here anytime with any questions about the Bespoke process.
At 12th HOUSE we provide an exclusive Custom fit and Sizing service to ensure your new ring will fit you perfectly.
OUR PROCESS IS SIMPLE
Upon purchasing your ring you will receive a complementary Sizing kit with instructions on how to measure your finger exactly, and confirm the sizing is absolutely perfect before your ring is made.
After confirming your exact ring size we will begin crafting your custom-made piece in our studio.
Choose options





create a ring suite
Ring suites are curated sets of rings designed to elegantly fit and harmoniously layer together, embodying the essence of commemorating extraordinary moments.

see our favorite combinations

About
midheaven collection
settings
Our signature designs are created to amplify the energy of the center stone. So if you love a Marquise cut stone, begin with the Marquise setting, etc.
gemstones
All gemstones are hand selected and sourced responsibly from our trusted partners to be top quality and traceable.
sizing
Our Custom Fit and Sizing service ensures your ring will fit perfectly. We will send you a ring sizing kit with two measuring methods to confirm your true size.