An extremely rare Laurentthomasite gemstone from Beravina, Mekaly region, Madagascar.

Laurentthomasite is a recent discovery, a new mineral species named in April 2019 after the French geologist, prospector and mineral dealer Laurent Thomas.
It has been approved and designated by the International Mineralogical Association as a member of the Milarite mineral group with chemical formula Mg₂K(Be₂Al)Si₁₂O_30.

Milarite has until now only been encountered in yellow or green colours, while Laurenthomasite displays an attractive greenish-blue tone.
Viewed with a dichroscope the gem displays distinct diochroism, a deep blue alongside a yellow-green colour.

This small gemstone is heavily included with liquid planes and growth tubes (as are most of the limited number of faceted gems currently available) and is consequently a bit rough around the edges, as can been seen in my images.
Nevertheless, this is still one of very few examples of this mineral which have been fashioned into a gemstone.

Images 5 to 7 are magnified views of the inclusion scene.

This gem comes with a certificate of authenticity issued by The National Gems Testing Laboratory of Thailand (GIT).

weight:  0.13 carat
shape:   Emerald cut
dimensions:   5.64 x 1.97 x 1.56 mm
treatment:  None