For the first time in the history of fine jewelry, more than half of all engagement rings sold in 2025 featured a lab-grown center stone — according to The Knot Real Weddings Study 2026. The era of the mined diamond as the unquestioned default is over. In its place, a more intelligent conversation is happening: one about ethics, beauty, craftsmanship, and what a stone actually means.

Two stones are leading this moment — lab-grown diamonds and moissanite. Both are ethical. Both are lab-created. Both are stunning. And both are available at Luxe Gemmes.

This guide is for the buyer who wants the real difference — not sales spin — before making the most meaningful jewelry purchase of their life. Here is what you need to know.

What Is a Lab-Grown Diamond?

A lab-grown diamond is a diamond. Not a simulant. Not a substitute. A diamond — grown in a laboratory using one of two technologies: High Pressure High Temperature (HPHT) or Chemical Vapor Deposition (CVD). Both replicate the geological conditions under which natural diamonds form, producing crystals that are chemically, physically, and optically identical to mined stones.

Lab diamonds are pure carbon arranged in the same cubic crystal structure. They carry the same hardness (10 on the Mohs scale). They exhibit the same refractive index. Under magnification, their inclusions look identical to those found in mined stones. If a gemologist examines one without documentation, they cannot distinguish it from a mined diamond — because, by every scientific measure, it is one.

The only difference is origin. No mining. No ecological destruction. No conflict supply chains.

Lab-grown diamonds are graded by the same institutions — GIA and IGI — using the exact same 4Cs system: cut, color, clarity, and carat. According to industry data, lab-grown diamond purchases have increased 239% since 2020, and the average carat weight for lab diamond engagement rings now sits at 1.9 ct.

If stone identity matters to you — if you want to say "it's a diamond" and mean it in the fullest sense — a lab diamond is your answer.

→ Learn more in the Ultimate Stone Guide

What Is Moissanite?

Moissanite has one of the more remarkable origin stories in gemology. It was first discovered in 1893 by Nobel Prize-winning chemist Henri Moissan — inside a meteor crater in Arizona. The material he found, silicon carbide, was so rare in nature that it couldn't be sourced. Today, all moissanite used in fine jewelry is lab-created, which means it has been conflict-free since its commercial introduction.

Here is what matters most: moissanite is not a diamond simulant. It is a completely distinct gemstone with its own identity, its own grading standards, and its own extraordinary optical properties. Comparing it to diamond as though it were trying to be diamond misses the point.

Consider the numbers. Moissanite's refractive index is 2.65–2.69 — compared to diamond's 2.42. A higher refractive index means more light is bent as it passes through the stone, producing more fire (the rainbow dispersion of light) and more brilliance. Moissanite doesn't approximate diamond sparkle; in terms of raw optical performance, it surpasses it.

Its hardness is 9.25 on the Mohs scale — second only to diamond among gemstones used in fine jewelry. It is entirely suitable for a lifetime of daily wear, including the daily mechanical stress that an engagement ring on an active hand endures.

Moissanite is its own gemstone. It has its own history, its own character, and in the right light — direct sun, candlelight, a dance floor — it is nothing short of spectacular.

→ Explore our moissanite and lab diamond options HERE.

The Real Differences — A Straight Comparison

Neither stone is objectively superior. They are genuinely different, and the right choice depends entirely on what matters to you. Here is a direct, side-by-side breakdown.