Orange-red, bright red, raspberry red: three stones that the eye confuses at first glance, and that are completely different as soon as you hold them to the light. Red chalcedony lets clarity through like wax, rhodolite breaks it into reflections, red corundum reflects it with the density of a precious stone. This guide provides the pointers to distinguish them.
- Red chalcedony, microcrystalline quartz, orange-red, translucent, waxy luster. Hardness 6.5 to 7. Carnelian is its known variety.
- Red corundum, aluminum oxide, bright red, hardness 9. Ruby is gem-quality red corundum.
- Rhodolite, transparent red pink to purple garnet, hardness 7 to 7.5, bright luster.
- Simple pointer: look at the light: translucent wax (chalcedony), bright reflections and transparency (rhodolite), density and bright color (corundum).
- Treatments, frequent heating for chalcedony and corundum, possible dyeing for chalcedony: the product page must state them.
The three stones in a table
What is the difference between red chalcedony, red corundum and rhodolite?
The three do not belong to the same mineral family. Their hardness, transparency and luster differ, and these are the criteria, more than color, that allow you to recognize them.
Red chalcedony
Is red chalcedony the same thing as carnelian?
Carnelian is orange-red chalcedony, the one whose color comes from iron. The term red chalcedony is broader: it can also refer to a red-dyed chalcedony. The shade matters for the purchase, a serious seller specifies if the color is natural, heated, or dyed. Our carnelian guide details its history, its varieties and its maintenance.
In the light, red chalcedony is recognized by its milky translucency: by placing it in front of a light source, it lets through a soft orange-red, without bright reflections. Its luster is waxy, not shiny.
Red corundum
Is red corundum a ruby?
Ruby is red corundum. The name ruby is reserved for gem-quality red corundums, transparent and with a bright color, which are among the four so-called precious stones. Opaque or very included red corundums, cut in cabochon, are the same mineral but of another quality: their color is less pure, their transparency low, and their place is rather that of a natural stone of character.
Its hardness of 9 out of 10 on the Mohs scale gives it very good resistance to scratches. Its density makes it noticeably heavier at the same size than chalcedony. Heating is very common to intensify its color, and some corundums of modest quality are filled with lead glass to hide cracks: this filling must be mentioned and requires avoiding aggressive products and ultrasonic cleaners.
Red spinel is often mistaken for a ruby, by its color. It is a different mineral species, of hardness 8, long sold under the name of ruby. Only gemological laboratory analysis decides.
Rhodolite
Is rhodolite a garnet?
Yes. Rhodolite is a variety of garnet, a mixture of pyrope and almandine, of pink-red to purple-red shade, which is often described as raspberry. Its name comes from the Greek rhodon, the rose. It is transparent, with a bright vitreous luster, and its hardness of 7 to 7.5 supports daily wear. It is generally sold without treatment.
It extends the garnet family, our garnet guide details the colors and maintenance.
How to distinguish them by eye
How to recognize a red stone?
- The light, in front of a light source, chalcedony lets through a milky glow, rhodolite becomes clear and bright, corundum remains dense, dark or opaque if it is included.
- The shade, orange for chalcedony, pink to purple for rhodolite, bright red for corundum.
- The weight, at the same size, chalcedony is clearly lighter than the other two.
- The luster, waxy for chalcedony, bright and shiny for rhodolite.
These clues guide, they do not decide. Heating, dyeing and filling are not seen by eye, only a gemological laboratory identifies them. Destructive tests, scratching or acid, damage the jewelry. For complete definitions, our article natural stone, dyed, reconstituted explains how to read a product page.
And the other red stones
Three other stones from the collection complete the red palette:
- The rubellite, bright red to pink tourmaline, hardness 7 to 7.5.
- The garnet, deep red, hardness 6.5 to 7.5.
- The carnelian, the orange-red chalcedony described above.
Which one to choose
Which red stone to choose according to use?
- For daily use, red corundum for hardness, rhodolite for luster and robustness.
- For the softness of a warm shade, red chalcedony, to wear with a little more attention to impacts.
- According to complexion, the orange of chalcedony accompanies warm undertones, the pink-purple of rhodolite the cold to neutral undertones. The guide of colors according to complexion gives the undertone test.
- According to the season, deep reds read well in autumn and winter, see the jewelry and seasons guide.
To compare all the stones of the collection, find which stone to choose and, for the core criteria, how to choose a natural stone.
Frequently asked questions
What is the difference between red chalcedony, red corundum and rhodolite?
These are three different mineral families. Red chalcedony is a translucent microcrystalline quartz (hardness 6.5 to 7), red corundum is an aluminum oxide of hardness 9, rhodolite is a transparent pink-red garnet (hardness 7 to 7.5).
Is red corundum a ruby?
Ruby is red corundum. The name ruby is reserved for gem-quality red corundums, transparent and with a bright color. Opaque or very included red corundums, cut in cabochon, are the same mineral but of a different quality.
Is rhodolite a garnet?
Yes. Rhodolite is a variety of garnet, a mixture of pyrope and almandine, of pink-red to purple-red shade. It shares the hardness and robustness of the garnet family.
Is red chalcedony the same thing as carnelian?
Carnelian is orange-red chalcedony. The term red chalcedony can also refer to a red-dyed chalcedony: the seller must specify if the color is natural, heated, or dyed.
Which red stone to choose for daily use?
Red corundum, of hardness 9, resists scratches very well. Rhodolite (7 to 7.5) also supports daily wear. Red chalcedony (6.5 to 7) requires a little more attention to impacts and heat.
How to know if a red stone is natural or treated?
No home test is enough. Heating is very common for corundum and carnelian, dyeing exists for chalcedony, and lead glass filling exists for some corundums. The product page must state the treatment.
Red palette
Find your red
Chalcedony, corundum, rhodolite, garnet: natural stones knotted by hand by Gulam and Amir.
See the collection